You practise in several commercial areas of law from finance to entertainment, but how much of your practice is finance-related? And are you happy with the balance or do you think lawyers are forced to specialise too much these days?

Sometimes I feel that the whole of my practice is finance-related, in that it finances my mortgage. More conventionally, I would estimate that about half my work comprises City disputes, derivatives work and cases involving hedge funds, private equity and the like. I have always tried to have a fairly broad-based practice. That’s partly because I like the variety of the work – it ensures I don’t get bored – and also because it’s often the case that an idea or principle from one area of the law or one business sector can be put to good work in another area of the law or in a different industry. A contract is a contract: it might be between two banks or between a pop star and his agent, but the principles of analysis and interpretation are the same. The only difference is that one makes better dinner-party conversation.

You personally act both for and against the big global banks. Is it difficult to do that without offending some clients?

Acting for and against a particular bank (or any former client) is not always a matter of choice: like every other barrister I’m subject to the “cab rank” rule which is, I believe, an important principle which the Bar must retain. But it can give rise to difficulties: it’s hard to explain to a former client why you are now acting against them when, in a previous case, you acted on their behalf. They don’t see their solicitors or foreign lawyers doing that and they often don’t understand why it should be any different at the Bar. But it’s well-known that it can be hard to find a large firm of solicitors to act against a big bank, and I would be concerned if that were to become the case at the Bar, too.

You are advising the FSA in their investigation into some of the products sold by banks in the run-up to the financial crisis. With your 360 degree view of the financial markets, did you and your colleagues see a financial crisis coming? And do you think the lessons have been learned to prevent a re-run in the future?

I can’t speak for my colleagues, but I can’t say that I foresaw the extent of the financial crisis – if I had, I would probably be on a beach somewhere and not in the Temple. And because every crisis is different, both in its causes and effects, I doubt I’ll spot the next one, either. But there is one danger sign I will be on the look-out for: people who buy or invest in financial products without knowing exactly what they are. Anybody who buys a financial product without being able to explain, simply and concisely, what that product is, and what are its risks, should not have bought it. That applies as much to bankers as it does to individual consumers.

You have been involved in many notable cases; but is there one in particular which stands out to you as ground-breaking?

Every case has its interesting features if you look hard enough, although it’s fair to say that some require a very detailed search. But if I had to pick one, it would be Unilever v Mercury Asset Management. This was the first time a pension fund (for whom I acted) had sued a fund manager for the mismanagement of the assets, by constructing an overly-risky investment portfolio. Market sentiment was that the claim was speculative, and the Trustees were increasingly concerned as one commentator after another wrote off their chances. The case settled after 11 weeks of trial, and although the settlement was, and remains, confidential, it was marked on our side by a celebratory lunch in a three Michelin-starred restaurant in Paris. The case had everything: interesting legal issues, colourful characters and a barrister who flew in each Monday morning after a weekend in New York (me: my wife was working there at the time). It also had – fortunately on our side – Jonathan Sumption QC and Deborah Finkler’s first-class team from Slaughter and May: a redoubtable combination.

With such a busy practice, how do you find time to relax and what distracts you best from the problems with which clients come to you?

I think my family would say that I don’t relax: if my Blackberry isn’t within easy reach I start to shiver and shake. My neurosis is such that I worry that if I don’t answer an e-mail on a working day within 3 hours my clients will assume I have died and will instruct someone else. But I don’t work on the Shabbat (Sabbath) and Jewish festivals: no e-mails, no phone calls, no papers. To paraphrase a Jewish saying: it’s not so much that I (try to) keep the Shabbat, but that the Shabbat keeps me.

What effect did taking Silk in 2009 have on you?

Taking Silk was more of a relief than anything else. It took me a week to complete the application form, and I dreaded the prospect of having to do it a second time. Silks’ Day had more of an effect on my family. My son’s reaction was that I looked “totally stupid” in the outfit (which was true); my father reiterated his amazement that any client should think my advice actually worth paying for; and my mother re-affirmed hers that any client should even consider instructing anyone else.

David Wolfson was interviewed by Matthew Lawson and Stephen Turvey of LPA Legal