Labour's rule changes are a dream come true for Tony Blair and the Tories, warned the first of five conference delegates to speak against the Collins proposals.

Hampstead and Kilburn constituency delegate Pete Firmin complained that party members had only seen the proposals a month ago.

“Important change requires far-reaching discussion in the party, but we have not been able to have that,” he said.

Mr Firmin said the proposals opened the way to the abandonment of collective trade union input into the Labour Party.

Another opponent of the measures, Wansbeck constituency delegate Steve Brown, seized on Ed Miliband’s reference to his father Ralph Miliband’s speech to conference nearly 60 years ago.

“Ed talked about his father calling for renationalising the commanding heights of the economy. Well, I would like to repeat that call,” said Mr Brown amid appreciative laughter.

GMB general secretary Paul Kenny told conference: “My union will be supporting these proposals wholeheartedly, not only supporting them but trying our damndest to make them work.”

But Mr Kenny cautioned that the opt-in proposals for individual trade unionists would “have an impact” on the party’s finances.

He also warned bluntly that the Labour Party would now have to reach out in a way it had never done before to convince trade unionists and others to become engaged with the party.

Doncaster constituency delegate Sally Jameson was one of over 20 speakers who backed what she termed the “bold, radical” Collins proposals. She predicted that hundreds of working people could be newly attracted to the party.

In a quirky intervention, Sedgefield MP Phil Wilson posthumously mobilised the late Communist miners’ leader Mick McGahey to justify his support for the proposals.

Mr McGahey had said “if we are not a movement, we are a monument,” recalled Mr Wilson.

Labour MP Keith Vaz reminded delegates that 25 speakers had come to the rostrum before him — but not one of them had been black or Asian.

Mr Vaz argued that the Collins reforms would “open up the Labour Party for black and Asian people.”