Security forces were on high alert tonight as the Queen prepared for her historic four-day trip to Ireland.
A ring of steel has been erected around Dublin after republican dissidents issued a bomb threat for central London on the eve of the trip.
Baldonnel Aerodrome is already in lockdown ahead of the arrival of the Royal flight at midday tomorrow, while traffic restrictions are being implemented in Dublin, Kildare, Tipperary and Cork ahead of the Monarch's arrival.
The Queen will make history when she arrives in Dublin and becomes the first monarch to visit Ireland, touching down at Casement Aerodrome at noon.
She will meet President Mary McAleese at her residence, Aras an Uachtarain, before one of her most significant engagements of her trip – a wreath-laying ceremony at the Garden of Remembrance, which honours those who died for Irish freedom.
But her momentous arrival is also shrouded with controversy and coincides with the 37th anniversary of the Dublin and Monaghan bombings, which killed 34 men, women and children.
Victim groups, which will hold a memorial for the dead in the morning, believe the bomb attacks were carried out by loyalist paramilitaries with British state collusion.
Armed British police officers will patrol the streets alongside thousands of gardaí and soldiers to protect the 85-year-old monarch and the Duke of Edinburgh during the largest security operation in the history of the State.
Fianna Fáil said the security threats in London were the actions of misguided criminals ignorant of the true values of republicanism.
Justice spokesman Dara Calleary said: “The message must go out loud and clear that the foolish actions of terrorists will not distract from what is an extremely positive and historic event in our country’s history.
“The State visit of Queen Elizabeth this week further proves the success of the peace process and the determination of people across Ireland and Britain to move on from the oppression of the past.”
The Queen will visit Croke Park, the scene of a massacre by British troops in 1920, and pay tribute to the 49,400 Irish soldiers who died in the First World War at the Irish National War Memorial Garden.
Other events will be staged at Trinity College, the Guinness Storehouse and Convention Centre in Dublin, the English Market in Cork, and the Rock of Cashel in Tipperary.
The Queen’s love of horses is reflected during visits to the National Stud in Kildare and Coolmore – the world-renowned international thoroughbred racehorse stud in Tipperary.
Sinn Féin, which also opposes the Queen’s visit, said the €30m security bill and disruption being caused with rolling road closures and parking restrictions was unacceptable.
Commuters have been urged to use public transport around the city, but several services will be cancelled as the Queen travels through the city.
Meanwhile socialist republican group Eirigi, which had planned to protest at an Irish Freedom Camp near the Garden of Remembrance, will instead hold an alternative wreath laying ceremony at the final headquarters of the 1916 rising on Moore Street.
A campaigner for victims of terrorism today said it was inappropriate for members of the Ulster Defence Association to be invited to a ceremony on Wednesday at which the Queen will lay a wreath in memory of Irish soldiers who died in the First World War.
Five senior members of the loyalist group, which declared a ceasefire in 2007 but is still on the Home Office’s list of proscribed terrorist groups, have been invited by President McAleese to attend the ceremony in Dublin.
But Jude Whyte, whose mother was killed by a loyalist bomb in 1984 and who now runs the Northern Ireland Victims Transition Forum, told BBC Radio 4’s PM: “I just find it quite unusual that the brigadiers of a mass murdering organisation are invited to meet the Queen when somebody like me is not.
“I have murdered nobody. I have killed nobody. I represent hundreds, if not thousands of people who died needlessly in this conflict.
“I think it would be far more important if they were invited to Dublin to publicly apologise to their victims... rather than that they meet somebody in this symbolic gesture, which I don’t believe has any real meaning in terms of their redemption.
“What they should be doing is going to visit graveyards.”