The Conservative Party has been urged to return a £160,000 donation it received from the wife of one of Vladimir Putin's former ministers for a tennis match with David Cameron and Boris Johnson.
Banker Lubov Chernukhin, whose husband served in the Russian Cabinet in 2000, made the winning bid for a doubles match last month.
It is one of more than £900,000 of donations that Labour say the Tories have received from people with links to the Russian government or "who may be hit by the sorts of sanctions" sought by the PM.
Opposition figures have called on the Prime Minister to ensure the money is returned, with MP Sheila Gilmore saying: "There can be no impression of conflicts of interest or hypocrisy at such an important time."
Come on David Cameron. Pay back the Tory donations from Putins pals
A Conservative spokesman said: "All donations to the Conservative Party are fully and transparently declared to the Electoral Commission and published on their website."
More top news
A lack of communication and teamwork skills prevents youngsters from getting a much needed foot onto the career ladder, according to a poll.
A dog who fell in a pool of hot tar has had a lucky escape after being rescues - and painstakingly washed - by an animal charity in India.
Glamour's 12th Annual 50 Best-Dressed Women List, voted for by readers, includes two Brits in the top 10.