Image caption The timing of the Queen's visit to the Irish Republic has yet to be announced

The Queen is to pay a state visit to the Irish Republic this year, the first by a British monarch since independence, it has been announced.

The Queen accepted an invitation from the Republic's President Mary McAleese, although no date has been released.

King George V was the last reigning monarch to visit the country in 1911 when it was then part of the UK.

Sinn Fein President Gerry Adams said the visit was an indication of a changed time but was "premature".

The success of the Northern Ireland peace process is thought to have made the visit possible.

'Watershed moment'

President McAleese's office said the timing of the visit would be confirmed at a later date.

BBC Ireland correspondent Mark Simpson said it was a "watershed moment" in British-Irish relations.

The war of independence and use of the British army in the Troubles in Northern Ireland strained relations between the UK and the Irish Republic for much of the 20th Century.

Analysis The historic visit by the Queen to Ireland is likely to take place in May and last a number of days. It will be seen by many as the final piece of the jigsaw in the Northern Ireland peace process. Months of tentative planning has already gone into the visit, but it was only when the Irish election was over that the visit could be confirmed. The Fine Gael leader Enda Kenny is set to become the next Irish prime minister, and he has signalled his strong support for a royal visit. For the Queen, it will be one of her shortest journeys, simply crossing the Irish Sea, but it will be a huge step in British-Irish relations.

The Queen also suffered personal loss when an IRA bomb blast killed her cousin Lord Louis Mountbatten on his boat in Ireland in 1979.

Our correspondent said: "During the times of the Troubles 40 years ago, some Dubliners actually burnt down the British embassy.

"Here we are four decades later talking about the Queen actually visiting Dublin."

He said he expected the visit to take place early in the summer.

The Irish government welcomed the trip which it said would "further improve" the "very good" relations between the two countries.

And a Downing Street spokesman said: "The prime minister is delighted that Her Majesty the Queen will be visiting Ireland.

"The visit symbolises the strength of the relationship between our nations and the bond between the British and Irish people."

The British ambassador to Dublin, Julian King, said the invitation symbolised how far the relationship between the two neighbouring countries had come.

"The UK's relationship with Ireland has never been closer, or more important," he said.

"Our common bonds enable the UK and Ireland to work together as a strong, modern, forward-looking partnership focused on issues that matter to the British and Irish people, such as growth and jobs."

But Gerry Adams said: "As Republicans, Sinn Fein is very aware of the symbolism of a state visit by Queen Elizabeth of England and of the offence it will cause to many Irish citizens.

"Particularly victims of British rule and those with legacy issues in this state and in the North. We are also very conscious of the attitude of our Unionist neighbours."

He added: "The president has invited the English monarch and Sinn Fein respects her right to do so.

"However we believe this visit is premature and we expect our views to be respected also."

When George V visited in 1911, he stayed in Dublin Castle - then the seat of British rule in Ireland.

He received a greeting of "almost unparalleled magnificence", according to reports at the time.