Deputy Prime Minister Nick Clegg has called on the Labour leadership to "come clean" about the "seriously dodgy" process for selecting its parliamentary candidate in Falkirk.

Mr Clegg said the Labour leadership appeared to be "puppets on a string" for the trade union bosses who provide the bulk of the party's funding, and described the controversy over the choice of a successor to MP Eric Joyce - who quit the party after a Commons bar brawl - as a "Monty Python parody of the Soviet Union".

Earlier this week, Labour leader Ed Miliband rejected calls to reopen the party's inquiry into the Falkirk selection battle, in the wake of the publication of emails from constituency chairman Stephen Deans which opponents claimed raised fresh questions about alleged attempts to rig the vote in favour of a candidate backed by the Unite union.

Union official Mr Deans and Unite's favoured candidate, Karie Murphy, were reinstated in September after a Labour investigation concluded without finding evidence of wrong-doing. Mr Miliband has refused to publish the inquiry's report amid questions over its key finding that allegations of members being recruited without their knowledge had been withdrawn.

Today another former candidate for the Falkirk nomination, Gregor Poynton, told The Guardian that he had paid for 11 members to join the Falkirk constituency party with a single cheque of £137 last July, adding: "I believe that I have at all times acted within the rules."

Mr Clegg said that events in Falkirk were an "absolute mystery".

He told LBC 97.3 radio: "It's like some sort of Monty Python parody of the Soviet Union. The whole thing is so mysterious, that the Labour Party is run like this.

"The Labour Party leadership appear to be puppets on a string run by these trade union bosses.

"How the trade union bosses then get elected, how they raise money, how they disburse money, is a complete and utter mystery to me.

"Something seriously dodgy clearly happened in Falkirk. It really is time the Labour Party leadership come clean with people about what happened so people know - given that this is a party that wants to run the country from May 2015 onwards - what kind of party it is."