British Prime Minister Boris Johnson has had an audience with Queen Elizabeth, marking the formal start of the 12 December general election campaign.

Mr Johnson left Buckingham Palace after formally asking for the Queen's permission to dissolve parliament.

He kicked-off the Conservative campaign to remain in power by comparing Labour leader Jeremy Corbyn with Soviet dictator Joseph Stalin.

Mr Johnson claimed the opposition leader shared Stalin's "hatred" of wealth creators.

Writing in the Daily Telegraph, Mr Johnson said that the Conservatives would "cheer, not sneer" entrepreneurs if they stay in office after the snap December general election.

The newspaper said Mr Johnson was exclusively launching the Tory general election campaign in the paper.

Mr Johnson said the Labour leader has taken a stance that demonises billionaires with a "relish and a vindictiveness" not seen since Stalin's attitude to landowners following the Russian revolution.

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

The comments came as Mr Johnson was set to use the launch of the Tories' campaign to stay in government to put withdrawal from the EU, the NHS and law and order centre stage in the campaign.

The Labour leader has insisted the party will deliver "real change" and that he will be a different kind of prime minister if elected on 12 December.

He said his party is well organised, well prepared and "utterly determined" to win the election.

Speaking in his home town of Telford, he said the election provided a "once-in-a-generation chance" to transform the country.

Mr Corbyn said he became an MP because real politics is about "bringing people together to stand up for their community".

He said: "I never thought MPs are special individuals with unique wisdom. It's not supposed to be a glamorous job."

Mr Corbyn added: "It's a platform for your community, not for yourself and that's how I see it."

Elsewhere, Scottish First Minister Nicola Sturgeon said the demand for a second referendum on independence would become "irresistible" if the SNP "wins" the election.

The SNP leader said resistance to allowing Scottish voters to choose for themselves would "crumble" in the face of such a result.

She told the BBC she wants a referendum in 2020.

Meanwhile, Green Party co-leader Jonathan Bartley said its £100-billion-a-year investment in a "Green New Deal" would be far cheaper than the "trillions" a climate emergency could cost.

The party kicked-off its election campaign in Bristol with a pledge to borrow £91bn and raise a further £9bn via corporation tax to invest in decarbonising transport and "retrofitting" insulation in homes.

Assistant Chief Constable Garry Cann has issued advice to parliamentary candidates and their teams to help them remain safe during the first December election in almost a generation.

It comes as female candidates such as Labour's Tracey Brabin and Liberal Democrat Luciana Berger both ruled out canvassing alone in the dark.

Mr Cann, the lead on elections for the National Police Chiefs' Council, told the BBC: "It may well be the case that candidates will want to brief their staff, many of whom will be volunteers, on things like working in pairs or making sure you have a charged mobile phone with you, making sure someone knows where you are so if you do need to call for help you can do so.

"It is right to say that these things usually pass off without significant incident and we have no particular reason to think it will be any different this time but we of course want people to look after their own safety."