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."
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Tobias Ellwood ran towards gunfire to give mouth-to-mouth resuscitation to Pc Keith Palmer after he was stabbed by Khalid Masood.
The terror attack carried out by Khalid Masood at Westminster that left four people dead lasted less than two minutes say police.