Boris Johnson says checks should be made on the Russian banker who bid £160,000 for a tennis match involving the London Mayor and David Cameron.
Speaking to Sky News, Mr Johnson appeared to suggest the match might not go ahead if her husband - Russian ex-finance minister Vladimir Chernukhin - turned out to be "an intimate or a crony" of Mr Putin's.
"I think you have to do stuff that actually hits Putin and his government where it hurts," he said.
"I know about this tennis match they volunteered me for with some geezer. It is very important full checks are carried out to make sure this is not someone who is an intimate or a crony."
More top news
Dramatic dashcam footage captured the moment a four-year-old girl was left seriously injured after falling out the back of a bus.
Tony Kim, who taught accounting at Pyongyang University of Science and Technology, was detained as he tried to leave the country.
Southern England will start dry and bright, and sunnier, colder weather will arrive in the north later in the day.