The tightest security measures in the history of the State are in place as Britain's Queen Elizabeth II and the Duke of Edinburgh begin their four-day State visit to Ireland.

Her first official stop was at Áras an Uachtaráin where she was greeted by President Mary McAleese.

British Queen's itinerary
AA Roadwatch travel updates
George V's 1911 visit
RTÉ's coverage
Watch a video of the Queen's arrival
Gallery: First day of the Queen's visit

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2359 20 people appeared at Cloverhill District Court tonight charged with public order offences.

2229 A suspect device was found on Blessington Street in Dublin at around 8.30pm this evening. Gardaí say the device has been made safe.

2114 Gardaí say 20 people arrested in Dublin City Centre are expected to appear at Cloverhill District Court tonight charged with public order offences.

A statement from Garda Press Office said one other person was released without charge.

1858 A protest organised by the Irish Anti-War Movement attracted around 80 people.

The group gathered outside Dublin's GPO to highlight the role of the Queen as head of the British armed forces fighting in Iraq and Afghanistan.

Speakers included People Before Profit TD Richard Boyd Barrett who accused the government of failing to give a straight answer on how much the visit is going to cost.

1852 Tánaiste Eamon Gilmore has said the policing operation put in place by gardaí during the Royal State Visit is necessary.

Mr Gilmore made his comments as gardaí confirmed a total of 21 people had been arrested in Dublin.

He said any public event attracts a ‘certain response’, he said strong security measures are needed and were felt to be appropriate by Gardai who put the plan in place.

1818 British Foreign Secretary William Hague has said there would be no glossing over the past during the visit.

Mr Hague said there would be great recognition of the past, which he said has and will continue to be seen during the visit.

He said the Queen's visit to the Garden of Remembrance was an important statement that speaks to the past.

1758 AA Roadwatch is reporting that the Phoenix Park has re-opened

1752 Former President Mary Robinson has said the Queen's visit would not have been possible without the peace process.

'For our relations between these two countries this is a very good visit,' she said.

'It would be good if she could meet larger numbers of people during her visit but security has to be taken seriously and there were sufficient indications that there might be a problem.'

1739 Gardaí say 20 people have been arrested because of disturbances in Dublin city centre. The are being held at the Bridewell, Pearse Street, Store Street and other city centre stations.

Gardaí confront protestors on Dorset Street (Pic: Ed Leahy)

1725 Dublin Bus says all services are back to normal. However, Dorset Street is still closed and minor diversions are in place.

1710 Queen Elizabeth has returned for a private evening at Farmleigh House in the Phoenix Park.

1659 North and South Quays in Dublin have also now opened to traffic again.

1657 Gardaí say that Dublin's O'Connell Street has now re-opened.

1655 Seven people have been arrested following violent disturbances at the top of Parnell St.

The trouble began at around a 1.45pm when demonstrators at the top of North Frederick Street began throwing missiles at unarmed uniformed gardaí manning the barricades.

The public order unit was deployed and the demonstrators were moved back up Dorset Street and Blessington Street and onto the surrounding areas.

Bottles, rocks, fireworks and other missiles were thrown at gardaí although there are no reports of any injuries.

Bins were overturned and refuse bags were set on fire as gardaí snatch teams moved in and arrested individuals for public order offences.

Officers say that many of the troublemakers are known to then.

The disturbances continued for three hours this afternoon.

1643 Taoiseach Enda Kenny has paid tribute to those who put together what he referred to as the jigsaw of peace that led to the visit of Queen Elizabeth II to Ireland.

Fianna Fáil leader Micheal Martin welcomed what he referred to as the historic day that reflects the transformation of relations between Ireland and Britain.

Mr Kenny told Mr Martin that he would raise the issue of access to files on the Dublin-Monaghan bombings with British Prime Minister David Cameron when he meets him tomorrow.

Mr Kenny said he had raised the issue at every opportunity with Mr Cameron in the past and would do so again.

1639 Queen Elizabeth signs a book of visitors to conclude her visit to Trinity College.

And meets some members of the public as she leaves:

1628 Former Taoiseach Brian Cowen has said the relationship between Ireland and Britain is one of mutual understanding and respect.

Mr Cowen said wreath-laying at the Garden of Remembrance was historic and an important explicit expression of the relationship between two countries.

He said the ceremony was moving and historic.

1615 According to RTÉs Political Correspondent David Davin Power, gardaí are still involved in a stand off with few dozen protestors on Dorest St.

1614 Dublin Bus says Camden Street is closed until further notice and buses are being diverted via Clanbrassil Street

1611 While meeting some of Ireland's cultural figures, Queen Elizabeth showed a great deal of interest in Ireland's national instrument, the harp.

1602 Watch a video of Danny Boy being played during Changing of The Guard at London's Buckingham Palace earlier

1558 Gardaí have arrested a number of people following disturbances at the top of Parnell Street.

Fireworks bottles and other missiles were thrown at gardaí. At least five people have been arrested so far.

A public order unit has been deployed and has forced the protestors back along Dorset Street.

1555 The British monarch enters the Long Room in Trinity College

1549 Queen Elizabeth stopped to wave at some students on her way into see the Book of Kells.

1545 Queen Elizabeth has arrived at Trinity College where she has inspected a facsimile of the Book of Kells.

1536 A number of missiles were thrown at gardaí by Éirigí supporters as Sinn Féin released a thousand black balloons in protest at the Queen's visit to the Garden of Remembrance.

Cans, plastic bottles and sticks were thrown before order was restored by protest organisers.

The incident occurred as the balloons were released from Sinn Féin offices on Parnell Square which is situated within the middle of the garda cordon. A number of Sinn Féin representatives including Aengus Ó Snodaigh TD were unable to gain access through garda lines.

1529 President Mary McAleese and Queen Elizabeth have both laid wreaths at the Garden of Remembrance.

1522 Queen Elizabeth has arrived at the Garden of Remembrance - an army officer welcomes 'Banríon Éilís a dó'

A large number of gardaí are policing the area and several bangs from fireworks thrown by protestors close to Dorset Street could be heard clearly as she walked through the gardens.

For a time shouts and jeers from the protestors could also be heard.

1517 Look back at RTÉ One's special programme Queen Elizabeth II in Ireland (part one | part two| part three)

1508 Gardaí have a number of public order units on standby in the vicinity of Parnell Square. It is understand a group of around 50 protestors are trying to make their way from Dorset Street towards the square.

Two loud bangs from fireworks have been set off within the past ten minutes.

Two people have so far been arrested during minor scuffles on O'Connell Street. Gardaí estimate that around 100 people are currently protesting in the area.

1505 Queen Elizabeth has left Áras an Uachtaráin and is now on her way to the Garden of Remembrance.

1459 RTÉ One's live coverage resumes

1436 Listen back to RTÉ's News at One's coverage of the Queen's arrival.

1424 Gardaí in riot gear have arrived at the Garden of Remembrance and are making their way towards the nearby protest.

1355 A number of protestors also gathered in streets beside the Garden of Remembrance in Parnell Square, but there have been no serious incidents .

1345 Around 100 supporters of Éirigí have now marched to the Garda cordon on Parnell Street - some distance from the junction with O'Connell St.

They say they are holding a peaceful protest. At least two garda lines are preventing access to O'Connell St and to Parnell Sq.

1329 Photo from O'Connell Street taken by @eimearmccormack

1324 Today in London, to mark the Queen's visit to Ireland, the band of the Irish Guards played The Derry Air (Danny Boy), The Irish Washer Woman and the Irish Salute during the Changing of The Guard at Buckingham Palace.

The music was arranged and conducted by Musical Director Major Wayne Hoplar.

The band has 43 musicians, many of whom are Irish. They were joined by the Pipes and Drums of the Scots Guards.

Some of the soldiers on parade today have just returned from a six-month tour of Afghanistan where they worked in support of British army medical services.

It is a rare event for the musicians to put on a special repertoire in honour of a state visit.

1320 The last of the Éirígí protestors have now voluntarily left O'Connell Street and are proceeding down Henry Street for their planned wreath laying ceremony at no 16 Moore Street.

1315 The Queen has planted an Irish Oak at Áras an Uachtaráin.

1307 Scuffles have broken out on O'Connell Street as gardaí try to remove protesters from near The Spire.

1300 There are security alerts at Phoenix Park Station and Drogheda Station, according to Iarnród Éireann.

Trains are not going into Drogheda Station and Northern Commuter Services and the Enterprise services are also affected. However, trains are running through Phoenix Park Station.

Maynooth line trains are running but will not stop at the station.

1257 Over 60 supporters of the Republican Éirígí Party are holding a sit down protest in O'Connell Street.

A large force of gardaí have begun moving protestors off the street.

The protestors are planning to lay a wreath at No 16 Moore Street where 1916 leaders made their last stand.

1255 This is the seventh time for President McAleese and Queen Elizabeth II to meet.

1250 Gardaí say the north and south quays in Dublin city centre are now open to traffic. South Circular Road, Coyngham Rd, Infirmary Rd, Parkgate St and Chapelizod Village have all reopened. However, the Phoenix Park still closed to traffic.

1229 The Queen was dressed in a jade green dress and coat by Stewart Parvin and a hat by Rachel Trevor Morgan.

The visitors are now being escorted to Áras an Uachtaráin by military and garda motorcylists. The leading military motorcyle is flying a Union Jack, said to be for the first time a Defence Forces vehicle to do so.

1228 The army bomb disposal team carried out a controlled explosion in Fairview Park in Dublin this morning following a security alert.

Gardaí say a suspicious device was found, which turned out to be an elaborate hoax.

1227 Dublin Bus says all buses serving Fairview are now operating back on their normal route after earlier diversion.

1221 British Ambassador Julian King and the Chief of Protocol at the Dept of Foreign Affairs Kathleen White went inside the aircraft to greet the visitors.

There was a slight drizzle a few minutes later when the Queen and Prince Philip stepped out of the plane.

Baldonnel

They were welcomed by Tánaiste and Minister for Foreign Affairs Eamon Gilmore, Irish Ambassador to Britain Bobby McDonagh, Deputy Chief of Staff Major General Dave Ashe and the GOC of the Air Corps Brig General Paul Fry.

The visitors then walked along a red carpet and through a guard of honour of 30 Air Corps personnel.

Queen Elizabeth was presented with flowers by eight-year-old Rachel Fox from Shankill in Dublin.

1217 Taoiseach Enda Kenny has arrived at the Áras where he will meet Queen Elizabeth II.

1209 The army bomb disposal unit has been informed of a suspicious device in the Phoenix Park in Dublin.

The unit is currently on route to inspect the device at the Ashton Gate.

1208 As visitors make their way to Ireland's capital this week, booking a room for two people in the Fitzwilliam Hotel or The Westbury Hotel will cost between €350 and €380.

This week, a night’s stay in three-star accommodation in the Dublin city area ranges from €48 to €133.

Next week, the same stay will cost between €35 and €85.

The Fitzwilliam Hotel has stated that the visit of Queen Elizabeth II has not impacted on the rate charged at their hotels. Instead, the upcoming soccer matches taking place in the city have increased demand for accommodation.

To stay in an executive room in the Ballsbridge Towers Hotel tomorrow, Wednesday 18 May, will cost €389. The same night next week will cost €179.

A spokesperson from The Irish Hotel Federation was unavailable for comment.

British Queen

1205 The British Queen has emerged from her plane. She is wearing a green coat and hat.

1202 No protestors have turned up for the Republican Sinn Féin demonsttration which was planned for the church at St Mary's Place in Dublin at midday this morning.

The only people who arrived were four journalists in response to a press release issued by the organisation.

1157 Plane carrying Queen Elizabeth II and the Duke of Edinburgh has touched down in Baldonnel.

Plane - Landed in Baldonnel before noon

1153 Three courts in Monaghan, Dundalk and Drogheda, which were cleared following a security alert this morning, will sit again from midday.

The Defence Forces said all three alerts had been declared hoaxes.

1144 Irish Rail says services will not stop at Phoenix Park station until further notice due to a request by gardaí.

1143 The first of the temporary road closures are now in place in the Dublin area.

Temporary road closures are in place in the Phoenix Park, on South Circular Road from Con Colbert Road to Conyngham Road, on Conyngham Road, Infirmary Road, Parkgate Street and in Chapelizod Village until 1230.

1132 Gardaí are investigating a suspect device at Fairview Park in Dublin.

The Army Bomb Disposal team is on its way to the scene. The device was discovered at about 10.45am and the area has been sealed off.

1131 The PSNI has advised all retailers in Belfast city centre to be 'vigilant' and on the look out for anything suspicious.

1128 Roads in and around Dublin city centre are very quiet ahead of the Royal visit, AA Roadwatch has said.

It appears that most people left their cars at home or are avoiding the city centre.

However, the traffic situation may change when more road closures comes into force at 11.30am.

1125 From 11.30am traffic management measures will come into place on the N4/M50 interchange.

1109 An Garda Síochána has released details of road closures and restrictions in counties Cork and Tipperary ahead of the Queen's visit.

1105 The Victoria Shopping centre in Belfast City has been evacuated. It follows reports of a suspicious object there.

PSNI officers are attending the scene.

1101 The British Ambassador to Ireland has said that many of the events on the Queen's itinery are designed to pay respect to the Irish State and to reflect on the nature of the past and future relationship between the two countries.

Ambassador Julian King said the Queen had thought 'very carefully' about what she will say at the State dinner at Dublin Castle tomorrow night, the only speech of her visit.

1100 A plane carrying Queen Elizabeth II and her husband is due to land at Casement Aerodrome in Co Dublin within the next hour.

She is the first British Monarch to visit the Irish Republic.

An 'extraordinary moment' in Irish history was how President McAleese described this visit, that moment is almost here.