The registrar's office in west London is a correct and neutral place: a vase of gerberas on a polished table in a carpeted room - the most modest and functional arrangements in the place where marriages are solemnised.
Karim and Valentina decided on a May wedding, as it is two years almost to the day since they met at the local branch of Kentucky Fried Chicken. He is from Algeria and she is from Portugal. Immediately attracted to each other, they have been inseparable for the past 12 months. Karim is an asylum-seeker whose right to remain was disallowed. He was tortured and traumatised in Algeria, but this is now one of the countries deemed "safe" for returning refugees. In other words, the army, which more than a decade ago cancelled elections that the Islamist Front Islamique du Salut (FIS) party was certain to win, has now quelled resistance sufficiently to reduce the number of deaths to a mere hundred or so a month. About 100,000 people have died in the past decade.
Karim is known to the authorities in his home country, having escaped from Algeria in order to avoid military service in the army. This same army had killed thousands of Muslim fighters, and countless civilians; many of these deaths were blamed by the army on Islamists, in an attempt to destroy the credibility of the FIS, and to undermine popular support for such political parties.
Since coming to the UK, Karim has always worked, mostly in the catering and hotel industries, where the demand for labour is so great that his status is never questioned. He has rarely earned the minimum wage. Valentina is from a middle-class family, and originally came to London to study English. She loved the diversity of the city and stayed on, doing casual work.
Just as the brief ceremony is about to begin, the doors are dramatically thrown open. Two officers of the immigration service step in. Marriages notified to all registrars are now subject to scrutiny; and when the names are checked, if they correspond to anyone who has been refused leave to remain, the immediate suspicion is that the marriage in question is "bogus".
The officers are both Asian - probably of Pakistani heritage. They seize Karim and drag him away for questioning: "You are in the country illegally. How long have you known this woman?" "Where did you meet her?" "What is your purpose in marrying?" "How much have you paid her?"
All Karim's friends - most of whom have been tortured or abused by the authorities in their various countries of origin - are petrified. The sudden seizure and removal of Karim reminds them of violent incursions into their own lives by police and secret service personnel. They hesitate, not quite knowing whether to remain.
Valentina, however, is a powerful, articulate young woman. She bursts into the neighbouring room where Karim is being questioned and asks the officials whether the disturbance of wedding ceremonies is part of their duties. She screams questions at them: "Are you married? When did you come to this country? Have you ever been separated from your wife?"
The officials question her commitment to the marriage. She responds with fury, spilling on to the table the many photographs she has had taken of herself with Karim, at his flat, at St James's Park, on the river, in front of the London Eye.
They say to Karim: "Do not think it will be easy for you to get a residence permit."
It appears, however, that even the professional breakers of bogus marriages are capable of a humanitarian concession. They leave - although promising, as they go, that this will not be the end of the story.
The registrar apologises for the interruption, and the wedding proceeds. The ceremony at the register office is now muted. Both Karim and Valentina are feeling very tearful.
They cling to each other. Afterwards, their friends hug them, offer their congratulations, create around them a thin, protective circle of affection. They had intended to go out for a celebratory meal, but no one feels like celebrating - Karim and Valentina are just thankful still to be together. They go for a coffee at Starbucks instead.
Still shaken, after coffee, the two of them get the Tube back to their two rooms in west London. Valentina feels their wedding day has been violated. That same day, the papers are full of stories of the forthcoming wedding of the heir to the Spanish throne: cheering crowds, elaborate celebrations, expense.
"If David Blunkett wants to look for bogus marriages," says Valentina, "he should start closer to home. What could be more bogus than royal marriages? They get married to produce an heir, and don't even give up their lovers."