Suria Clarke's family realised that she must have been in the World Trade Centre's north tower when the first plane hit, long before the discovery of an email she had sent from her desk that morning provided the conclusive proof. A poignant reminder of a life that once was, in all other respects the email seemed academic. In fact it was anything but.

For the families of the victims of September 11 - in particular, for British families such as the Clarkes - the grief of the past two years has been compounded by the bureaucratic complexities of the aftermath of the tragedy. Questions of identification, compensation and insurance are still not fully resolved. All manner of legal niceties have had to be grappled with. The unearthing of documents has been long and painstaking. Relatives of the dead have had to supply DNA samples. And the fact that there are two countries involved has only made the process more tortuous.

In all this the existence of Suria Clarke's email - sent to a friend she was planning to meet for lunch later that day - turned out to be a vital part of the jigsaw of her life that her family has had to piece together for the authorities. Before life insurance companies pay out, they like to know that the person insured really is dead. In the absence of any remains, how could the Clarke family prove that Suria - a 30-year-old public relations executive for Cantor Fitzgerald - had actually been in the building at the time of the attack? The email to her friend Michelle - that was how. "But that's September 11 for you," says Suria's brother Tom. "It's been like that from top to bottom. Just deeply, deeply harrowing."

Tom Clarke, along with his mother Alexandra, have been leading figures in the UK Families September 11 Support Group, a loose association of British families formed a few months after the event with the aim largely of easing the immense practical problems that had arisen. "It took a while for families to want to talk," says Mr Clarke, a 30-year-old journalist on the science magazine Nature. "People were dealing with so much. It had been such a public thing, and everyone had been too shocked." But the fall-out was so complicated - "even getting death certificates took months and months of paperwork" - that it made sense for people to work together.

Not all the families of the 67 British victims have chosen to be part of the group. But the vast majority have, and Mr Clarke thinks that its work is one of the few good things to have come out of the tragedy. This week, on the second anniversary of the attacks on New York and Washington, the support group's work to create a memorial garden dedicated to the British victims - to be sited in Grosvenor Square, opposite the American embassy - will come to fruition. "Everyone's very pleased about that," says Mr Clarke. "It's made us feel better to have done something. We're very cohesive."

Suria's personal circumstances meant Mr Clarke's family has been lucky, he says, compared with others. "Suria was single, she had no dependants, and my parents are around and both together." Where victims had divorced parents, spouses, ex-spouses, or children, the financial arrangements become much more complicated.

The primary source of compensation for families of victims - both in the US and in Britain - is the US government's Victims Compensation Fund. Using a sliding scale based on the dead person's age, dependants or lack of them, earnings and earnings potential, the fund's committee has to decide how much each victim is "worth". Payments have averaged over $1m, but Mr Clarke explained that to benefit from the fund, families had to agree not to pursue any legal action against any American body - be it the US government, an airline or an airport.

"I don't think people were in a hurry to get blood," Mr Clarke says, "especially when it's so hard to see where the blame lies. I think the deeper you look into what happened, the thinner the blame is spread. I think it was very difficult for people to identify a culpable party." As far as Mr Clarke knows, no British family is pursuing legal action.

The Clarkes, who are from Richmond in south-west London, are one of many families whose application to the fund has yet to be processed. But in common with every other British family, they did receive a one-off payment from the US Red Cross of around $50,000. Some of the British families' Red Cross money has been channelled into the Support Group, enabling it to cover, among other things, the cost of travel to meetings and of publishing a newsletter that monitors coverage of September 11 in the media and keeps people informed of legal and other developments.

Meanwhile, victims' families have had to come to terms with the fact that the death of their loved ones has never stopped being referred to. But for Tom Clarke, this has not been an entirely negative consequence. "I don't think there was a single day in 2002 when you didn't read about it," he says, "and it's pretty much the same now. There are constant reminders everywhere. I run into people every day and it crops up. I have to turn away, change the subject. But at the same time people do find some comfort in the fact that it's remembered so frequently and so widely. A good example was the memorial service at St Paul's last year. It was attended by some very high-profile people, and that recognition was appreciated."

What undoubtedly upsets Mr Clarke is the way that 11 September - and by implication his sister's name - has been used as the justification for the wars that have since been waged by the US and Britain. "I remember going to the ceremony in New York soon after September 11 when Tony Blair was there. I didn't manage to speak to him, but I did speak to Cherie. I asked her to impress on her husband to make sure that as little harm as possible follows from all this. She said of course she would. But I knew they would want to kick some ass. I'm really cynical about these things. I know how politics work. They were always going to invade Iraq, but I don't think Iraq is anything like as strongly connected to September 11 as they would like to make out. What happened that day highlighted a profound problem that the world had, and we're no closer to a solution now than we were then. Indeed, things might be worse."