Is it a self-defence mechanism how sometimes in order to allow ourselves to muddle through, the mind erases an episode or a batch of unhappy memories from the hard drive?
That may be case with John Major and possible gaps in his recall of jousts with Boris Johnson in a past life.
I've tracked several interviews given by the now 76-year-old former prime minister in recent times. But I've not yet seen a reference to those awkward encounters from more than 20 years ago.
Yet I distinctly remember a phase in the 1990s when the then British government leader was under fierce pressure from what he described to ITN’s Michael Brunson as 'the b----ds' in the Conservative party. (The derogatory term he used almost rhymes with 'custards').
The Tory Eurosceptics were a minority at the time but they were adept and relentless at causing trouble for their leader. I witnessed John Major field news conference questions at the conclusion of draining summits of EU leaders.
Often the prime minister was tired and no doubt he knew that he would have to face into more trouble as soon he crossed the Channel and returned to the floor of Westminster.
Towards the end of such media events, from the considerable number of British journalists a question would be lobbed in from the Brussels Correspondent of the Daily Telegraph. The dispirited prime minister would attempt to provide an anaemic response, free of scope for misinterpretation or controversy.
But, as became clear from such encounters and many times since, when Boris Johnson smells blood he is a formidable force.
The Tory press, with Boris Johnson featuring prominently, was a very real factor in John Major's demise. Twenty-two years after Prime Minister Major’s defeat by a young Tony Blair in a British General Election, Boris Johnson is now installed in Downing Street.

Eurosceptics are no longer a minority – they run the Conservative party that Boris Johnson leads.
In a vivid example of changed times, next week John Major will join forces with anti-Brexit campaigner Gina Millar in a legal challenge to oppose Prime Minister Johnson's decision to suspend the Westminster parliament for five weeks.
Installed in Downing Street, Mr Johnson has with him as 'Operations Manager’ the single-minded genius, Dominic Cummings.
In the Blair ‘new Labour era’ Alastair Campbell and Peter Mandleson brought the dubious craft of spin-doctoring and brand management to a different level. But in their 38 days in charge, Boris Johnson and Dominic Cummings have given a whole new meaning to the strategy that the end justifies the means.
During the past week, they didn’t just confront their political opponents, they blasted them off the road.
They have identified the chronic weakness at the heart of their main enemy, the Jeremy Corbyn Labour party. Their gut instinct tells them that if the macho power-play they unleashed in Westminster leads to a general election, they have the means to see off Labour and return with more seats than they currently hold.
Their focus for the coming week will be to maintain the upper hand in Westminster. Legal challenges in Scotland, Belfast and London seem unlikely to trip them up.
Opposition parties, supported by some dissenting Conservatives, will try to bring in parliamentary measures to thwart them.
If such an against-the-odds ploy does indeed fail, the next option could see Jeremy Corbyn triggering a vote of no-confidence in the Prime Minister. Boris Johnson doesn’t seem terrified by the prospect.
Nobody died in Westminster during the past frenetic week. But 40 years ago last Tuesday, 27 August 1979, 23 people were killed needlessly on the island of Ireland. Eighteen of them were British soldiers, victims of the IRA at Narrow Water, in Co Down.
The first 800lb fertiliser bomb was hidden under hay on a parked trailer. It was detonated as two lorries transporting soldiers passed. Six men died in that explosion.
Many of the survivors sought shelter at the nearby stone gateway to Narrow Water Castle. Thirty-two minutes later, another bomb exploded, claiming 12 more lives.
Some of the frightened soldiers looked across the water to Co Louth and saw activity in the trees. Their gunfire killed a completely innocent civilian, Michael Hudson. His father, a Sligo native, worked on the estate of Queen Elizabeth in London.
Earlier that day, another IRA gang killed four people in a bomb attack on the boat of Lord Louis Mountbatten off the coast of Co Sligo.
During the night, the explosives had been planted on the small fishing vessel, moored in Mullaghmore Harbour. Those who hid the lethal material drove away from the area after carrying out their work.
But others remained to track the movements of the Mountbatten family to their boat from their holiday base at Classiebawn Castle.
They pushed the remote control button that set off the explosion, killing 79-year-old Lord Mountbatten, the 83-year-old Dowager Lady Braebourne, their 14-year-old grandchild, Nicholas Knatchbull, and 15-year-old Paul Maxwell from Enniskillen, who had a summer job on the boat.
In May 2015, Prince Charles came to Mullaghmore and made his peace, just as his mother Queen Elizabeth had done during her first State Visit to Ireland in 2011.
Earlier in the day at a ceremony in Sligo, Prince Charles said: "I could not imagine how we would come to terms with the anguish of such a deep loss since, for me, Lord Mountbatten represented the grandfather I never had."
He went on to say: "Through this dreadful experience though, I now understand in a profound way the agonies borne by so many others in these islands, of whatever faith, denomination or political tradition."

In relation to the often difficult historic relationship between Ireland and Britain he said: "We need no longer be victims of our difficult history with each other. Without glossing over the pain of the past, we can, I believe integrate our history and memory in order to reap their subtle harvest of possibility.
"Imagination, after all, is the mother of possibility. Let us, then, endeavour to become the subjects of our history and not its prisoners."
Those remarks by Prince Charles were made in Sligo, 30 miles from the border, 13 months before the Brexit referendum.
Classiebawn Castle, the holiday home of his mentor and great uncle, Lord Mountbatten, was built in the late 19th Century for the 3rd Viscount Palmerston, whose family had vast tracts of land in the northwest.
He twice served as British prime minister and had three different spells as Foreign Secretary, spanning 15 years.
But he was a member of the opposition when he spoke during a second reading of the Roman Catholic Relief Bill in the House of Commons on Wednesday 18 March 1829 (the same House of Commons that will dominate news bulletins next week).
Palmerston's speech, headed "On the Catholic Question" runs to 32 pages and was priced and 1s 6d. The paragraph at the bottom of page 20 begins: "The population of Great Britain, by the returns of 1821, was fourteen millions; the population of Ireland at the same period was about seven millions."
Last Tuesday, new figures released by the Central Statistics Office detailed how the population of the Republic of Ireland is now 4.9 million, its highest level in 150 years.
It has increased by more than one million since 2002. Add in the 1.8 million people living north of the border and the population of the island of Ireland – approximately 6.7 million – is almost back to the "seven millions" referenced by Palmerston in the House of Commons 190 years ago.
Palmerston's 1821 population figure for Great Britain was 14 million. Today it is approximately 66 million. Heavily influenced by the consequences of The Famine, the population of Ireland dwindled but now, almost two centuries on, it is back to 1820s levels.
During the same period, for a variety of reasons including industralisation, prosperity, immigration from many regions of the world, including Ireland and parts of its former empire, the population of Great Britain increased almost five-fold.
In Ireland’s case, since the foundation of the State joining the European Union in 1973 has been the greatest driver of profound and lasting change.
In what was then a smaller club, Ireland and the three other poorest member states, Greece, Portugal and Spain, were the greatest beneficiaries of financial transfers, in Structural Funds, Regional Funds and Social Funds packages.
Watch - From the Archives: Dubliners' Reactions to Joining the EEC (1972)
Of the four countries, Ireland developed a reputation for being the most efficient 'absorber' of the Brussels aid. Even before the roll-out of those wealth transfer policies promoted by the European Commission president, Jacques Delors, Ireland's farmers were the first beneficiaries of the European Community membership, through the Common Agricultural Policy.
The European Single Market policy, heavily supported by Margaret Thatcher, guaranteed free movement of goods, capital, services and labour.
It removed internal frontiers and it is sometimes forgotten that the barriers were removed on 1 January 1993, making the single market policy a driver of normality in border areas, 20 months before the 1994 IRA ceasefire.
Just as becoming part of a European family encouraged Irish agriculture to look for markets beyond their nearest neighbour, other sectors also pursued opportunities on the European mainland.
The IDA began developing what became a highly successfully strategy, selling Ireland as an ideal base within the European Union for US multinational investors.
The 'Reeling In The Years' images don’t lie. The EU factor helped to transform and modernise Ireland with resources that the State itself was not in a position to provide.
It offered a future that could be different and better than what had often been a difficult past. It was about a lot more than money.
Christy Moore’s most popular song is, arguably, Joxer goes to Stuttgart, an account of a football supporter’s adventures at the 1988 European Championships. The fact that Ray Houghton sticks the ball in the English net helps. But the punch line tells how the Fraulein from the Rhine shows up in Ballyfermot.
EU membership had a transformative effect on so many levels: equality in the workplace; pension entitlement; working time directives. In my own case, I availed of a right, verified in the EU’s Luxembourg-based Court of Justice, to access health services in Sweden that were not available in my own country. Thanks to the access provided as a right through the €112 mechanism, I am above ground to write these lines.
Catherine Day, a citizen from Ireland, one of the smallest member states, became Secretary General of the European Commission. David O'Sullivan also served in that role. Pat Cox was elected President of the European Parliament. Mairead McGuinness is currently serving a second term as a senior Vice President of the same institution. Ray MacSharry did not go to university but as the EU Commissioner for Agriculture, he supervised the reform of the Common Agriculture Policy.
The thread that links those individuals and the wider story they tell is how EU membership coincided with a relatively young country beginning to question itself and daring to be ambitious for a future that would be better than its past.
On the neighbouring island, the pattern was often different. As a relatively wealthy EU member state, the UK was not entitled to the level of transfers diverted to Ireland.
While the smaller island was benefitting from membership of a bigger club, in keeping with a trend that is a feature for much of the 20th Century to the present day, Britain’s influence as a world power was in a pattern of decline.
Europe warily accepted the UK’s entry application in 1973, having turned down earlier requests. Past complex history was below the surface, but never buried without trace.
Tension was a constant in the UK/EU relationship - miles fighting with kilometres, gallons fighting with litres, pounds fighting with kilogrammes. Concessions, rows and a loss of control became part of the narrative.
The unavoidable truth, the issue at the heart of our current dilemma is that while we are next door neighbours, Ireland and the UK view membership of the European Union differently. In our case, sometimes due to no more than coincidence but more often because of the relationship, EU membership is synonymous with positives.
In contrast for the UK, significant phases of 46 years attached to the Brussels club coincided with a sense of decline and a loss of control. For tolerant, fair-minded people life become more pressurised, schools, hospitals, trains, streets became more crowded. In a nutshell, it seemed that life was becoming harder.
It is a complex truth about British/Irish affairs that while we had completely difference experiences of European Union membership, being part of the Brussels club had a positive impact on our relationship as next door neighbours.
Ireland's membership of the wider European family reduced its "peripheral island beyond a larger island" inferiority complex. When operating within a larger group, the two next door neighbour states often discovered they had many shared instincts and values.
Prompted by the enlightened SDLP leader, John Hume, the British and Irish governments used the shared European identity as a layer of flooring in the Good Friday or Belfast Agreement.
The Republic of Ireland dropped its 62-year-old territorial claim to Northern Ireland. The Amended Article 2 in the Irish Constitution, endorsed by referendum, includes the lines: "It is the entitlement and birthright of every person born in the island of Ireland, which includes its islands and seas, to be part of the Irish Nation. That is also the entitlement of all persons otherwise qualified in accordance with law to be citizens of Ireland."
The Boris Johnson I worked with in Brussels was bright and comfortable in what seemed like cultivated eccentricity. His capacity to stretch a mixture of facts and suppositions into front page stories irked the hell out of many of his British press corps colleagues.
They frequently found themselves getting late night phone calls from their news desks about the latest Boris anti-Brussels splash.
His father, Stanley, had once worked as a European Commission official. His then wife, Marina Wheeler, is an able lawyer and daughter of the distinguished BBC correspondent, Charles Wheeler. John Palmer, then Europe Editor of The Guardian, was the first person I heard predict through gritted teeth that Boris would one day end up as prime minister.
There has been a pattern throughout his ascent to the most powerful and challenging job in British politics. In many aspects of his life, he does not hang around. He gets restless. He can change his mind, his stance and his surroundings, easily and completely.
The two-term eight years served as Mayor of London are the exception rather than the rule. Stay in the EU, leave the EU. Backing Theresa May, plotting against Theresa May. Sending conflicting signals about his opposition to the expansion of Heathrow Airport. There are many more examples.

Dominic Cummings has the ways of a gambler with a disdain for each-way bets. His use of social media platforms was an enlightened tactic during the Brexit referendum campaign.
He harnessed resources that were beyond the reach or understanding of his opponents. But the campaign's promised repatriation of Brussels money to the NHS and the focus put on "outsiders" were the actions of someone who is prepared to bet the house to do what is necessary in pursuit of a goal.
Tony Blair seemed a very able gambler. His "go for it" instincts were vital to the achievement of the Good Friday Agreement. Without his actions, there would be no agreement. But after George Bush persuaded him God would be on their side, he gambled on intervention in Iraq. And the rest is sad history.
There is little of nothing to indicate that the Johnson/Cummings axis understands the complex story of our islands. It is unreasonable to expect that they might appreciate our completely different experiences of European Union membership.
It is entirely consistent with Boris Johnson that he would equate the challenges along the border on the island of Ireland with congestion charges issues in the Greater London area.
In the Brexit referendum campaign masterminded by Cummings, there was no allowance made for the UK/EU land frontier on the largest island to the west of Scotland.

John Palmer’s prediction about the one destined to become prime minister has indeed come true. A consequence of reaching the highest office is one is expected to perform. There is no hiding place on centre stage.
It was the initiative of the Johnson/Cummings axis that had Queen Elizabeth approve the Westminster Parliament Prorogation Order last Wednesday morning. It was the monarch’s son who said in May 2015, "Let us, then, endeavour to become the subjects of our history and not its prisoners".
The genius of Dominic Cummings during the Brexit campaign involved convincing decisive numbers of voters that in an EU-free future they would be able to return to a version of the past that may not have existed.
He and Boris Johnson are a partnership, the likes of which was not seen in Downing Street in modern times.
There will be a reduced need for the drama, escapism and stretched storylines of 'Love Island’, ‘Fair City’ or ‘Game of Thrones’ in the days ahead. Westminister will remain compulsive viewing.