A lot of workers are taking industrial action in the UK, from rail staff to rubbish collectors. The most unusual protest over pay comes next week when thousands of criminal barristers go on indefinite strike to push the government to raise their legal fees.

This is also a rewarding time for many professionals, with pay rates for young lawyers, consultants and bankers jumping sharply in the “war for talent”. McKinsey, Bain and Boston Consulting Group have increased base salaries for new MBA graduates in the US to about $190,000. But the talent war is being fought on a different battlefield to the criminal courts.

The real incomes of barristers who defend those on criminal charges have fallen steadily over two decades to an average of £47,000 last year (depressed during the pandemic by not being able to appear in court). That is less than some City law firms offer their new trainees straight out of university, while top solicitors and commercial barristers can take home £2mn or more.

Criminal barristers do a vital job for society by defending people who are in dire trouble, but their pay is modest compared with many in commercial law. It may be soul-destroying to spend your working life advising on legal structures for private equity deals, but your soul fetches a fantastic price.

The gulf between the fortunes of criminal and City lawyers is a tale of our times. What was once a reasonably balanced trade-off in career choice — human interest and ethical purpose for pretty good pay, versus somewhat higher rewards for dustier intellectual challenges — has become one-sided. If you ever hope to afford a house in London, go commercial.

Criminal barristers’ age-old problem is performing most of their duties for clients who cannot afford to pay them. It was covered from the 1960s by the routine granting of public legal aid for crown court defendants, but making a good living has become tougher since fixed fees for barristers were introduced in 1997, and steadily squeezed from then on.

Having their incomes set by a government monopsony is not criminal barristers’ only difficulty. They are also self-employed, often need to pay their own travelling expenses, amass high student debt, and are poorly paid in the early years. They face the pay disadvantages of public sector work, without the accompanying security or pensions.

Compare this with commercial barristers and City of London solicitors who work for banks, multinationals and private equity firms. They always had clients who could afford to pay, and there are many more clients now. Barristers’ chambers and City law firms have plunged into a war for legal talent.

The minimum pay for pupils (trainees) at London chambers is a little over £19,000 per year but chambers specialising in tax law pay five times that amount. Meanwhile, law graduates joining one of the five “magic circle” firms such as Clifford Chance are paid about £50,000 as first-year trainees, rising to £120,000 or more as newly qualified solicitors.

Globalisation is one reason for the growth in London lawyers’ pay (rates are lower outside the capital). US law firms that pay employees even more have moved into the UK, putting the magic circle under recruitment pressure. The global legal market can be very rewarding — Clifford Chance’s revenues rose to nearly £2bn this year — but it is competitive.

The spread of private equity deals is a second reason. Just as private equity firms create activity for banks, they draw on lawyers for advice on mergers, tax, restructuring and all kinds of legal activity. They are also ready payers. “They do not care so much about the bills because they do not pay them, their investors do,” says one law firm partner.

So, while criminal barristers work in a fixed labour market, with only a financially stressed government responsible for paying most of their fees, their commercial counterparts operate in a global one, with deep-pocketed financial clients. There is no mystery about who prospers.

It is not solely a UK phenomenon. New York is a highly rewarding place to be a commercial attorney, but those lawyers who work as public defenders face similar financial stresses. The city’s Legal Aid Society complains of losing many attorneys and paralegals due to comparatively low pay.

Nor is it confined to the law. The pay decisions facing graduates are clearer cut than a generation ago. It used to matter less whether a graduate job tapped into a global market; whether it was in the private or public sectors; and whether it was transactional or socially useful. The divides are very stark now.

But the plight of British criminal barristers is a special concern. Sir Christopher Bellamy did not exaggerate when he called legal aid “essential to maintaining a modern, peaceful and democratic society” in his review last year. If it is irrational to work for anyone but the rich, we are all in trouble.

Away from the criminal courts, the war for legal talent remains intense, as it is in consulting and banking. What happens when most of that talent is sucked into commercial transactions, leaving little for anything else?

john.gapper@ft.com