Queen to make groundbreaking visit to Ireland

Troops, police and even ground-to-air missiles were being deployed ahead of Queen Elizabeth II's groundbreaking visit to Ireland, a trip charged with symbolism but fraught with risk.

Encouraged by the largely successful peace process in Northern Ireland, which has made her sensitive visit feasible, the queen will become the first British monarch to set foot in the Republic of Ireland. When a British sovereign last came, a full century ago, all of Ireland was still part of the United Kingdom.

The monarch's presence, however, is still resented by some in Ireland who bristle at the legacy of British rule, with some predicting violent street clashes while others fearing a terrorist attack.

Bomb threat in London

London's Metropolitan Police said it had received a bomb threat to central London from a dissidents Irish Republican group on Monday.

Security will far exceed measures used for the 1979 visit of Pope John Paul II or for the 1990s visits of U.S. President Bill Clinton.

The national police force has cancelled all leave and drafted in officers from rural areas, boosting the security detail to 8,500.

They also have borrowed two mobile water cannons from Northern Ireland's police.

The queen's four-day trip to Dublin, Kildare, Tipperary and Cork comes as a Catholic-Protestant government in the neighbouring British territory of Northern Ireland has just been re-elected, marking another peace milestone.

The Irish Republican Army violence of decades past counting among its victims the queen's cousin, Lord Louis Mountbatten, killed when the IRA blew up his yacht in 1979 has given way to the group's 2005 renunciation of violence. Only small splinter groups still plot bloodshed across the border.

Tour includes Guinness brewery

One of the queen's first actions Tuesday will be to lay a wreath at a Dublin memorial honouring Ireland's rebel dead, a surprisingly direct gesture toward Britain's opponents in the bloody 1919-21 guerrilla war of independence.

The queen's trip will highlight Ireland's many charms, from the Guinness brewery to its Europe-leading horseracing industry, and stunning historical monuments such as the medieval Rock of Cashel. She will be joined by her husband, Prince Philip.

The Irish Defence Forces have deployed ground-to-air missiles at key locations, plan to shut down airspace over Dublin and other locations in tandem with the queen's movements, and are keeping more than 1,000 troops in reserve.