The Unite union has written off loans worth £75,000 to Jeremy Corbyn's second leadership campaign.

The cash will now be declared by Mr Corbyn as a donation to his leadership campaign, which raised more than £100,000 last year.

Unite gave Mr Corbyn's campaign two 'indefinite' loans - one of £50,000 and another of £25,000 - both of which were written off on November 23, Mr Corbyn's latest declaration of interests reveals.

Len McCluskey, the Unite general secretary, propped up Mr Corbyn's ailing leadership last year after Labour MPs launched a coup against him.

A senior Labour source told MailOnline the £75,000 represented a 'load more Unite members' money wasted'.

Jeremy Corbyn's leadership campaign received loans totalling £75,000 which have now been written off by Unite. Mr Corbyn - pictured at a leadership relaunch this week - won the Labour crown for a second time last September

Unite general secretary Len McCluskey is one of Mr Corbyn's closest and most powerful allies

A spokesman for Mr Corbyn said: 'All donations for the 2016 leadership campaign above the legally required threshold are registered and published.'

A Unite spokesman said: 'In 2016, Unite members voted overwhelmingly to support Jeremy Corbyn as Labour leader. The support the union gave reflected this decision.

'All monies have been properly declared by the parties concerned.' But opponents pointed out that only hard-left activists would have attended the meeting backing Mr Corbyn.

The loans have already been declared to the Electoral Commission in their current form but have not yet been updated to donations in the watchdog's database.

Mr Corbyn has another loan of £50,000 outstanding to the Momentum campaign group borne out of his first leadership campaign in 2015.

Unite wrote off a £50,000 loan to Mr Corbyn's first leadership campaign in September 2015 on the day he became leader.

Unite leader Mr McCluskey is one of Mr Corbyn's most powerful supporters.

His support during an attempted coup by Labour MPs last summer helped ensure Mr Corbyn kept his job as Labour leader.

The write offs were revealed in Mr Corbyn's latest register of interests in Parliament. The first entry shows a £25,000 loan received on July 7 that was written off on November 23

A second loan of £50,000 was received by the campaign on August 11 and it was also written off on November 23

Mr McCluskey is embroiled in a re-election battle for his post as general secretary after resigning early to head off internal enemies.

His rival Gerald Coyne slammed Mr McCluskey for wasting time and money playing politics instead of representing members' interests.

In his manifesto for leader, Mr Coyne said: 'Our current leader spends too much of his time - and your money - playing at Westminster politics.

'I will never try to be the puppet master of the Labour Party.'