London Mayor Boris Johnson urged Russia's oligarchs to sue each other in the city's courts, in contradiction of the government's policy of discouraging "libel tourism".
"If one oligarch feels defamed by another oligarch, it is London's lawyers who apply the necessary balm to the ego," Johnson told the Confederation of British Industry's annual conference in London on Monday.
"I have no shame in saying to the injured spouses of the world's billionaires: if you want to take him to the cleaners, take him to the cleaners in London, because London cleaners will be grateful for your business."
The Defamation Bill, currently going through the upper chamber of Parliament, requires the plaintiff to show that Britain would be clearly the most appropriate place to bring a case, rather than the one where it would be easiest to win. The then justice secretary, Ken Clarke, said in March of last year the bill was designed, among other things, to stop US citizens from suing US publications in London.
"We are trying to dissuade libel tourism on a point of principle," Prime Minister David Cameron's spokeswoman, Vickie Sheriff, said.
Johnson argued that such cases, with the associated legal fees, are welcome.
He said the money would go "into the pockets of chefs and waiters and doormen and janitors and nannies and tutors and actors and aromatherapists - and keep the wheels of the economy turning, and put bread on the tables of some of the poorest and hardest-working families".
In his speech, Johnson also called for "more moral leadership from the leading bankers of today" in return for fewer attacks on them.
"It is not good enough for them to lick their wounds behind the stuccoed walls of their Notting Hill schlosses," the mayor said. "We need the great financiers of today to make the case for capitalism, not just by the wisdom of their investments, but by their philanthropy."
"But they won't give if they feel persecuted and despised; and indeed there is a risk that they will take their business away and we won't succeed as a society if we actively set out to sabotage a sector in which we are strong."