Gordon Brown is making a last-ditch attempt to stop Jeremy Corbyn

Gordon Brown will break his silence on the Labour leadership election on Sunday as he adds his weight to efforts to halt the Jeremy Corbyn bandwagon.

The former Prime Minister, who enjoys more respect among Labour members than Tony Blair, will make a speech in London entitled “Power for a Purpose –the Future of the Labour Party”.

Although Mr Brown’s office refused to comment, allies believe he will endorse Yvette Cooper amid signs that she is gaining ground in her battle with Andy Burnham to emerge as the “stop Corbyn” candidate, after a powerful speech attacking the Left-winger on Thursday.

Cooper supporters hope that Mr Brown’s speech could repeat his decisive intervention ahead of the referendum on Scottish independence last autumn. Ms Cooper is married to Ed Balls, who was Mr Brown’s closest policy ally.

Ed Miliband, who like Mr Brown has been under pressure to speak out against Mr Corbyn, is thought likely to maintain his silence.

More: Six things Gordon Brown did that were not a complete disaster