MoneySavingExpert founder Martin Lewis is to sue Facebook over scam adverts using his image.

The commentator and financial journalist is claiming defamation over allegations that the site is publishing scam adverts using his image causing vulnerable people to hand over thousands of pounds to criminals.

He said the company had hosted more than 50 of the scam ads and that it had failed to act because it was motivated by "greed".

Mr Lewis said the legal action, due to be launched on Monday, was the result of months of frustration with scammers who were piggybacking on his reputation and preying on Facebook users with outlandish get-rich-quick scams.

Supporters have handed over thousands of pounds in good faith, only to find the advert has nothing to do with Mr Lewis or his company.

"Vulnerable people are the ones being scammed and the ones being hurt," he told the Daily Telegraph. "It has to take some responsibility."