The Liberal Democrats should give back a £2.4m donation after the jailing of the man who ran the company behind it, says the Commons deputy leader.
Businessman Michael Brown was based in Spain Photo: The Times
Labour's Nigel Griffiths said the donation from millionaire businessman Michael Brown should be paid back after his imprisonment for perjury.
The Liberal Democrats say they acted in good faith and the Electoral Commission found their acceptance "permissible".
But Mr Griffiths claimed the cash was received without adequate checks.
The Lib Dems received the money before the last general election.
Brown, 40, was jailed for two years last month after admitting committing perjury and making a false declaration to obtain a passport.
Brown, who is based in Spain, became the Lib Dems' biggest donor before the general election.
There is no suggestion the court case has anything to do with the party.
Mr Griffiths told BBC1's Politics Show on Sunday: "This £2.4m should be returned immediately.
"The man who gave it to them is in jail and Ming Campbell and the Liberal Democrats used that £2.4m in seats like mine - tens of thousands of pounds in each seat - to try and buy the seats.
"It's now time, since they've been caught out, that they should return that money. They took the money without adequate checks, it's clear to me."
The Electoral Commission watchdog carried out an investigation last year after it emerged that Brown was not registered to vote in the UK.
But the watchdog later found it was "permissible" for the party to have accepted the cash from his UK-based company, 5th Avenue Partners.
A Lib Dem spokesman told the Politics Show in a statement: "At the time of the donations, the company was carrying on business. It rented premises and it had a substantial turnover.
"The Liberal Democrat Party acted in entirely good faith in relation to these donations."