As Mr Brown had not been resident in the UK, and not on the electoral register, at the time he made the donation, he used a bogus company name (5th Avenue Partners Ltd) as the official legal donor.

Mr MacNeil said:

"I understand Chris Huhne has made a complaint to the Metropolitan Police over Labour's illegal funding scandal.

"Clearly, it is important that political donors are not only fully identified and beyond reproach, but also actually entitled to make such donations in the first place.

"In this respect, I would politely challenge both the Liberal leadership hopefuls to commit themselves to repaying the £2.4million donation made by Michael Brown back in 2005. The question is, are Chris Huhne and Nick Clegg prepared to lead by example?"

ENDS