London - Ireland's Michael D. Higgins arrived in London on Monday ahead of the first state visit by a president of the republic since it gained independence from neighbouring Britain.
The visit comes three years after Queen Elizabeth II made a groundbreaking trip to the republic, which helped to heal deep-rooted unease and put British-Irish relations on a new footing.
Higgins' return visit will be seen as an official sign of further progress following the hard-won peace in Northern Ireland, which remains part of the United Kingdom.
Such an exchange of visits would have been impossible even at the turn of the millennium.
Higgins was met at London Heathrow Airport by Viscount Hood, lord-in-waiting to the queen. The state visit formally gets under way on Tuesday.
“We are at a very interesting point in history, when we have, following Her Majesty's visit to Ireland, such good relations between our people,” Higgins said before taking off.
“My hope for the visit, at the end of it all, is that people will, in ever more numbers, come to share in experiencing the history, the present circumstances and culture.”
For state visits, Britain summons up all its traditional pomp in a bid to cement cultural, diplomatic and economic ties.
Queen Elizabeth, 87, plays host at a castle or a palace and the red-carpet visits typically involve ceremonial events, lavish banquets, cultural visits and political talks.
On Tuesday, Higgins, 72, a poet and a former arts minister, will arrive in a procession at Windsor Castle, west of London.
He will inspect a guard of honour before a private lunch in the castle.
Higgins later visits Westminster Abbey in London and addresses both houses of parliament.
The day finishes with a state banquet at Windsor Castle, which will be attended by Northern Ireland's Deputy First Minister Martin McGuinness - a move that would once have been unthinkable for the former IRA paramilitary commander.
Higgins' trip is set to consolidate relations between London and Dublin following Queen Elizabeth's highly charged visit in the other direction three years ago.
It was the first visit by a British monarch since her grandfather king George V in 1911, before the republic won independence from Britain in 1922.
For many, hearing the British monarch open her keynote speech in Irish - a stunned president Mary McAleese could be heard repeatedly saying “wow” - was the biggest of several small gestures that had a powerful effect.
She won praise for facing thorny historical issues head-on, such as bowing her head at the memorial for those who died fighting for Irish freedom from Britain.
“There are a lot of very difficult memories and it would be to my mind wrong to suggest to anyone that you should as it were, wipe the slate clean,” Higgins said before arriving in Britain.
“I think Her Majesty in coming to Ireland and addressing for example issues of relations between our two peoples was doing it the right way.”