Finally there was a lab unit in which we learnt how to analyse fingerprints, hair and fibre, and how to write court reports I've found accident analysis the most challenging. I had to get a bank loan to do the course because as an Irish student studying in England I wasn't eligible for any scholarships. The theme of the course is "crime scene to court" and there are two semesters with four units each, as well as a three-month research project. In the first semester we covered forensic principles, such as crime scene analysis and crimes against the person including things like DNA analysis and blood-splatter patterns. It's a rapidly expanding area, with new technology being used to solve crimes that happened years ago.

I'm from Ireland, where forensic science is not offered at the undergraduate or postgraduate level, and that's why I ended up over here in London. After my undergraduate degree in science, specialising in microbiology at Trinity College, Dublin, I took two years off, travelling in New Zealand and earning money for my MSc. Forensic science courses are popular these days, which is not surprising given the subject's exposure on television, in newspapers and in books. As a teenager I was always reading Patricia Cornwell thrillers and I was fascinated by the way scientists can reconstruct events at a crime scene. In Albany School the hope will nonetheless be that Teach First teachers, now a real asset, stay put.Only time will tell if Jacob Kestner, who says he has no idea what he'll do in future, will be persuaded by one of Teach First's so-called business partners to cash in his Kestner dollars in exchange for real ones, and leave Albany behind.. But for the schools on the ground that are just beginning to see their Teach First staff sparkle, and for whom teacher retention does matter, this is an inevitable frustration.My public relations minder reminds me, somewhat tetchily, that Teach First alumni will always remain "ambassadors" for education, whether they stay in teaching or not. As David Grayson, director of Business in the Community and a Teach First enthusiast, explains: "Participating businesses get more motivated, more rounded and more skilled employees" from the scheme.This is great news for Teach First's corporate neighbours in Canary Wharf.

This is why, perhaps, over half of those graduating from the scheme chose to remain in teaching this year.But why does Teach First remain "agnostic" about keeping its much-improved teachers in schools once their two-year commitment is up, and indeed provide avenues for them to leave? "Part of the reason people are interested in what we offer is because the skills you garner from the classroom can be applied in the world of business," Wigdortz suggests.This pleases business sponsors. Besides, Teach Firsters are adamant that the experience quickly transforms them into better teachers. "The first term was a bit panicky - we were just figuring out the basics like how to do a lesson plan." Another teacher tells me, in private, that the summer training camp left him feeling wholly unprepared for the disheartening levels of discipline he encountered.But inexperience is necessarily a problem for all new or under-trained teachers - not just Teach First recruits. Nonetheless, head teacher Dawes admits that the lack of hands-on experience in the classroom is the one aspect of the scheme she would have improved.Alison Richards, 24, who started with Teach First and is now on the coveted fast-track scheme, would also have liked more London-teaching practice before the start of her first term. Karina Rhoden, in Year 8, agrees: "Although they can be more fun sometimes, I've had ones that don't know how to get respect from their class," she reveals, as those around her nod with approval.James Delaney, a Year 9 student, concludes the way forward for Teach First: "training - give them more training." My minder flashes James - although not me - a terse smile.Teach First argue that they do provide supplementary training through mentoring, evening classes and weekend sessions in the first year of teaching. "They're more likely to use modern technology - like the new interactive whiteboard," says Jemma Gumble, Year 9, of her Teach First teachers. "They're more with it," says Grace Webb, one of Albany's star Year 11 pupils, "kind of easier to relate to."That said, students do have concerns about their Teach First educators.

"Sometimes they fail to get a hold on the class, and things get unruly," explains Andrew Smith, a bright Year 10 pupil, while my Portland minder - who insists on sitting in on interviews - shuffles awkwardly. "If I'm using a textbook I feel like I'm not doing my job right," he says, recalling a time he conducted a whole lesson in mime, "in order to teach the importance of non-verbal communication".Kestner dollars and miming teachers are just the kind of innovative teaching that students appreciate. Skillfully deploying a diverse array of props - including a tin of sardines, a Tesco card, and a walkman - Kestner gives his Year 7 class a brief introduction to historical relativism. His class is captivated, like neat rows of rabbits staring, in silence, at a brilliant headlamp. Those students who get their answers right are rewarded with a "Kestner dollar" note, which, they proudly tell me, they can later exchange for popcorn.Pieter Kooyman, 23, another teacher in his second year of the scheme, also likes to experiment with new teaching methods. "My fear was that they were totally untrained teachers." But after talking to colleagues Dawes took the risk and, although she would ideally choose to recruit fully trained teachers - "how could I not?" - she doesn't regret the decision. "They bring a new energy to the school - new ideas, new contacts - and now we actively seek out Teach First teachers."Indeed, those who decided to Teach First at Albany are an impressive crop: four are already in leadership positions within the school, one as head of sixth form.Jacob Kestner, a fresh-faced but disarmingly confident teacher, and a favourite among all the students I speak to, is a case in point.

But now, after a renewed focus on teaching and discipline, the school is out of "serious weaknesses" and results are on an upward trend - a turnaround that Dawes attributes, in part, to a battalion of 11 Teach First teachers."When I first got the flyer from Teach First I just thought 'no way'," recalls Dawes. By 2008, there may be as many as 500 Teach First sparkles planted each year in Britain's most challenging schools.But how has the scheme fared so far, after just two years in operation, for the students and schools who receive these teachers? According to Portland - the public relations agency that provides pro bono representation for the charity - the message glows: students are inspired, schools are turned around, and, if that wasn't enough, "future leaders are born caring about education".To make sure I don't miss the point, Portland provided me with a Soviet-style minder to monitor my visit to one of Teach First's success stories, Albany Secondary School, in Enfield.When head teacher Lynne Dawes arrived at Albany in early 2003, Ofsted had determined the school to have "serious weaknesses" - one step away from special measures. Once recruited, 90 per cent of participants complete the two-year placement. According to Teach First's internal surveys - released to The Independent this week - head teachers are, on the whole, highly satisfied: 98 per cent of them ask for more Teach First teachers.No wonder, then, that Teach First is set to balloon. With more support pledged by Gordon Brown in the budget, the scheme will travel to Manchester next year, before rolling out to three more cities from 2007. Brett Wigdortz, 31, a former management consultant from McKinsey, and now CEO of Teach First, plays down the American link. "We just discovered that it is true that exceptional and inspirational teachers make the difference in challenging schools," says Wigdortz, "and we found a pent-up demand for something like this among exceptional graduates."Wigdortz points out that the charity has received more than 3,000 applicants in just three years, making it one of the most popular employers for graduates.