When Gerry Adams leads his party's delegation into No 10 Downing Street this afternoon there will be television cameras and a media scrum jostling to explain the historic significance of the event. By receiving Mr Adams and his colleagues, Tony Blair is delivering on his promise, made in Belfast within days of his general election victory, that if the republican movement opted for democratic methods Sinn Fein would be treated in exactly the same way as any other political party.
That in itself is important, particularly if it has the desired effect of strengthening support for Mr Adams and confounding the doubters within the republican movement.
Gerry Adams has not been backward in talking up what he sees as the historic importance of a republican leader telling a British prime minister how he sees the situation "for the first time since 1921". He has said that he wants to discuss the "unfinished business of creating a united Ireland".
This is understandable, if a trifle overblown. The talks at Stormont are reaching another critical point. By early next week Senator George Mitchell hopes that all parties will agree a document identifying the key issues that will have to be discussed when they reconvene in the new year. This is a difficult moment for Sinn Fein. There are signs that the leadership is more jittery than it cares to admit about the emergence of a group, formed by republican dissidents, called the Thirty-Two County Sovereignty Committee.
This is not simply because one of the key figures is a sister of Bobby Sands. Rather, it is that the group has articulated the suspicions which many grassroots activists feel about the whole thrust of the peace process.
These people argue, first, that the present talks are heading towards "a modernised version of partition" and, second, that by signing up to the Mitchell Principles of non-violence Sinn Fein has virtually conceded that unionists will dictate the outcome of any negotiations. The issue of the unionist veto is back on the agenda.
Over and over again these past few weeks the complaint has emerged that the unionists will not talk directly to Sinn Fein delegates and that this "refusal to engage" by Mr Trimble and his colleagues amounts to denying the republican movement's right to be involved in negotiations.
That may change in time. One has the impression that each side is listening very carefully to what the other has to say. But for the moment at least the subject is taboo. As the unionists see it, too many concessions have already been made to Sinn Fein and there is still deep suspicion about the party's long-term intentions. The problem with this stance is that it vindicates those on the republican side who say that the unionists are not prepared to engage in inclusive negotiations and that, in short, nothing has fundamentally changed. Sinn Fein is still being denied the full recognition of its right to represent the interests of the people who voted for it.
At last Friday's meeting of the Forum for Peace and Reconciliation at Dublin Castle, Martin McGuinness was interviewed by Charlie Bird about the present state of play. Speaking with evident exasperation, Sinn Fein's chief negotiator at the Stormont talks said the current focus on Articles Two and Three "missed the point completely". People needed to remember, he said, that the conflict in the North was the result of "inequality, injustice and discrimination." In relation to today's visit to Downing Street, Mr Adams has said he will be asking Mr Blair to consider the effects of "almost eight decades of injustice, an absence of democracy, oppression and intermittent conflict" as the most serious consequences of partition.
This week, as happens almost every week, there have been stories in this newspaper and others relating to the urgent need to tackle this "equality agenda", which covers a broad spectrum of libertarian issues as well as those relating to discrimination.
Gerry Adams and Martin McGuinness are not the only high-profile Sinn Fein representatives who have been about the party's business in England this week. Pat Doherty and Gerry Kelly have been part of a delegation visiting IRA prisoners serving their sentences in British jails. A press conference in Dublin on Tuesday, organised by the Irish Commission for Prisoners Overseas, drew attention to the painfully slow pace at which prisoners serving long sentences are being transferred to Ireland, although the legislation to make this possible has now been in place for two years.
Some of these prisoners are now entering their third decade in jail, often in extremely harsh conditions. At Tuesday's press conference Lord Hylton appealed to the British and Irish governments "to make a special effort" to effect the transfer on humanitarian grounds of the four IRA prisoners who formed the Balcombe Street gang, and who are all serving sentences of over 30 years.
Other stories, equally familiar but none the less important for all that, have been raised. The Committee on the Administration of Justice, which has played such an important and principled role in focusing attention on civil liberties issues, has launched a report on policing in Northern Ireland based on the fruits of 18 months research in other divided societies. It hopes this may provide an opportunity for a wide-ranging community debate which avoids the trap of allowing the police to become a part of the process of political barter.
These issues matter to both communities but are particularly important to the people Sinn Fein represents. They need to see that the peace process has brought them tangible gains and that this has happened because Sinn Fein is able to operate effectively as a political party. We know there are fractious and difficult times ahead as both sides grapple with the major constitutional issues and prepare their own supporters for the compromises that will have to come. The challenge facing this State in making it possible for unionists to feel a greater sense of belonging to the island as a whole is one with which we have not yet begun to grapple. That is a topic for another day and another column. For today it is enough to see that Tony Blair has taken another necessary risk to ensure that Gerry Adams's peace strategy - and his gradualist approach to the unfinished business of history - are seen to be credible.