Mr Lammy's views on discrimination and being black at the Bar could be seen as unfashionable. He does not deny that racism exists ("there are a lot of isms at the Bar") but is no militant and believes in tackling problems from the inside.
"You have first to understand the system before you can competently take issue with it," he says. "Otherwise, you challenge the wrong things for the wrong reasons and succeed only in cementing what already exists."
Now 22, Mr Lammy comes from one of London's most run-down areas, Tottenham, where his family still lives.
A strongly Christian upbringing led to the choir in his local church and then to a scholarship as a chorister at Peterborough Cathedral and then as a board-er at the King's School in Cambridgeshire, where life was "a little difficult at first".
"I was the first black chorister," he says. "But I was just myself and got on with it. I really enjoyed singing and I enjoyed school." Then came reading for an LLB at the School of Oriental and African Studies at the University of London, where he graduated with an upper second, and another scholarship, for the Bar vocational course.
He describes the path to the Bar as a race with hurdles. One hurdle is discrimination.
"You've just got to get on with it, using tenacity and persuasion," he says. "It is not always appropriate to get angry. We know what overt racism is, we can legislate against it, the Bar has codes against it, there is a lot of discussion and angst. I believe the way to deal with it is to come to terms with the institution you want to be involved in. To change it you've got to understand why it exists. That means signing up for all the pomp and mystique."
The point of the Bar is that it aims to be a meritocracy, in which individuals are, and want to be, judged on their records, he believes. "It is like fitting into a new family. But it is a two-way equation. I know my worth, and want others to be receptive to that." His approach may have been shaped by a multicultural home life, but it also has a foot in realism. At a time when the Bar is under threat from competition, he says, it needs to take on people offering all manner of skills and experience.
He has a 12-month pupillage in his chambers, a civil set, whose members he describes as "friendly and incredibly bright". His work will be in professional negligence, construction law, but mainly in medical negligence, a growing area of practice, which he describes as the humane end of law. It is concerned with people, he says, but also offers intellectual satisfaction in tackling ethical issues.
Civil practice has fewer black practitioners than criminal work, and he says: "I am delighted that I haven't found myself pushed into the areas of law traditionally associated with ethnic minorities; family, crime and immigration. I have found a civil practice that gives me the ability to expand outside what to some extent has been an established box. It's important to me that I am not `ghettoised'."
This is not to deny his roots. "When I wanted to become a barrister at the age of 15 or 16 I was aware of those who made it before me. If you saw a black face in a legal journal you were influenced by what they had to say."
He admits to having been "damned fortunate. I know what prejudice is, I know what poverty is - not in my own family but I can't go back to Tottenham without seeing it all around. It is not my place to tell others to deal with racism with tenacity and persuasion. I'm talking about the Bar, which is made up of educated people who will go on to process the force for change in this country."
It is hard to imagine David Lammy not doing well in his career, but he says it is too difficult to talk about future ambitions at this stage.
"I'm just hungry to learn, and to become a very good barrister, and to be judged on that. Where that leads, I don't know, I am after all still only 22.
"I am learning more this year than I ever have. I'm happy to be here and I work within that. It's not to do with being black, it's to do with loving the law."Much of his free time is taken up with work for the Free Representation Unit, and he also uses travel to "live law". On a trip to Jamaica he worked at the Council of Human Rights, dealing with death row prisoners, and he also undertook a placement programme in New York.