IN the ambassador's office in the British embassy, Ivor Roberts's bookshelves are almost bare, his belongings still mainly in boxes in Glencairn, the house in the Dublin mountains where he will live for the immediate future.

The Merrion Road embassy is strikingly solid, its concrete, steel and toughened glass exterior a monument to history. It was a less secure embassy, in Merrion Square, that was burned out in 1972 during an angry post-Bloody Sunday demonstration. It was close to Glencairn that Mr Roberts's predecessor, Sir Christopher Ewart Biggs, was assassinated in 1976.

He says this violence visited on a British embassy and ambassador in Ireland does not really weigh on his mind. "Maybe I'm being unusually optimistic or cavalier, but I don't feel the hand of negative fate. On the contrary I'm coming at a particularly favourable juncture for a British ambassador. I believe in understanding the past but not being locked into or a prisoner of the past."

He expresses the hope that the days of violence are over: "Practically everyone in the island of Ireland understands it is not the way to settle things."

He answers a question on the oppressive nature of the necessary personal security in a general way, rather than dwelling on the specific problem of being British ambassador in Ireland. "A depressing part of my adult life is that security plays a greater part in everyone's life. When I first joined the Foreign Office you just breezed in, there was no real control, but that has all changed. It's a sad development."

During the week he brought his 16-year-old daughter into Temple Bar one evening. "I think I'm going to like Dublin," she said. She is in school in Britain but will spend holidays here, as will his sons, aged 19 and 22, one of whom attends university in Scotland, the other in England.

Glencairn has been sold, but the ambassador still lives there as the embassy has entered a leaseback arrangement with the new owner. Mr Roberts is going to look for a suitable residence or a site on which to build, but he will make no rash decision. The new ambassador has Irish (and Welsh, English and Italian) blood. His mother was Italian, his grandfather on the other side was Welsh while his grandmother's family came from Co Waterford.

He played rugby until at the age of 28 his leg was broken in a club game. "It was taking me so long to recover that I seemed to spend more time recovering from injury than playing, so I thought in terms of fitness it would be more useful to think in terms of refereeing. I took a course and learned the laws. The problem with rugby as opposed to soccer is they seem to change the laws every season."

He comes to Ireland amid continuing difficulties in the Northern Ireland peace process, but also at a time of unprecedented warmth in British-Irish relations. This has not emerged overnight, he says, but has been built up over the years by the present political leaders and their predecessors.

"A key factor is that there is a realisation that the problem in the North is one that is capable of being resolved," he says. "The enormous injection of energy and activity into resolving it, not only from the governments but from the parties, has added to the mood in a way which we haven't seen before. Then from below you have the democratic underpinning from people of the island of Ireland shown so massively in the referendums.

"There is a feeling that the poison is gone out of the system. I've been enormously struck while I've been here by the very genuine warmth of people who come up to people and say how welcome the British ambassador is and how they know I'm going to have a great time here and they hope very much I am going to have a happy time here.

"I have heard nothing but positive vibes. It has been as positive and warm a welcome as it is possible to be, in stark contrast to the last place, arriving in Belgrade to war and sanctions. That was very gloomy."

Gloomy Belgrade was the posting which so far has defined him most in the minds of foreign policy watchers. Critics of the international community's response to the break-up of Yugoslavia and the subsequent Bosnian war have commented negatively on his role there from 1994 to 1997, initially as charge d'affaires and later ambassador. In particular, an oft-repeated line is that he was "too close" to President Milosevic, and that his style was closer to that of player than referee.

However, Mr Roberts says that among the criticism there was lavish praise as well. "The people who pay me are the British government, and the Foreign Secretary described me as one of the outstanding diplomats in the Foreign Office.

"I was asked to get inside Milosevic's head and find out what he was thinking . . . If you're not close to him I don't know how you are supposed to understand what he is about."

He became perhaps the most influential ambassador in Belgrade. The US envoy, Richard Hol brooke, described him as "erudite and charming" although "he seemed excessively pro-Serb".

Since leaving Belgrade he has been on secondment to St Andrew's College, Oxford, writing a soon-to-be-published book on former Yugoslavia. His Australian wife, Elizabeth Smith, a former Australian diplomat, is also a Balkanologist, speaking fluent Serbo-Croat and writing a book on Montenegro.

At 52 and at the outset of a new posting to Ireland, he now has the opportunity to be defined by much more than Belgrade. Asked what he would like to be able to say at the end of his time here he says: "Any ambassador would like to feel that he has made a difference in the quality of the relationship.

"I think I start off with a lot of pluses. I start off with the support of the relationship between the Taoiseach and the Prime Minister which goes down to all levels between the two governments, and obviously the ambassador is one of the people who benefits from that. I would like to think that I have played some part in pushing that process on.

"I can't predict where our relationship will be in three or four years' time, but I would like to look forward to a time when the various bodies under the Good Friday agreement have been set up and are running, functioning in a way that people don't think about these things in amazement any more.

"They simply hear there is going to be another meeting of the British-Irish Council or the intergovernmental council or the North-South council, and these bodies will no longer seem surprising."

Would it now be a logical step for Ireland to join the Commonwealth? "There is a great Welsh proverb: he who would be a leader must be a bridge. Bridge-building has been one of the cornerstones of the progress that has been made in relation to Northern Ireland.

"I think the Commonwealth is another bridge-builder between continents, between countries, and has played a very positive role. That said, a decision on joining the Commonwealth is a matter exclusively for the Irish people and their parliament and Government."

He says that when watching footage of the Northern Ireland Assembly on television recently he was struck by the changes that have taken place. "People who a very short time ago were sworn enemies . . . were arguing vigorously, being tough with each other but in a manner no different than in other parliaments and assemblies. "Perhaps we are all taking it too quickly for granted. It was very striking, very moving."