The Queen's visit will be the first by a British monarch to the Republic of Ireland.The Queen is set to begin the first visit to the Republic of Ireland by a British monarch. Irish police say up to 4,000 people are involved in security for the four-day trip, which comes amid a rise in dissident republican violence.The Irish army has made safe a "viable" improvised explosive device found on a bus bound for Dublin. Another bomb threat has been investigated in London.

Mary McAleese will formally welcome the Queen at the president's Dublin home.King George V was the last reigning monarch to visit the country, in 1911, when what is now the Republic was then part of the UK.

The Queen was invited to visit by Mrs McAleese, who will formally welcome the monarch at her home in Dublin's Phoenix Park.

The Queen will attend events at Trinity College Dublin, the National War Memorial Gardens in Islandbridge and at Croke Park stadium.

Croke Park is the home of Gaelic football where in 1920, during the Irish War of Independence, British forces fired into the crowd at a match, killing 14 spectators and players.

The Queen is also to make a speech at a state dinner at Dublin Castle.

There are plans for the Queen and Prince Philip to visit the Irish National Stud in Kildare, as well as the Rock of Cashel in County Tipperary and a technology park in Cork.