Labour MP Jim Sheridan has launched a broadside at "out-of-touch" Lord Mandelson following the anti-union peer's public attack on the party's plans to take on profiteering power firms.

Paisley and Renfrewshire North MP Mr Sheridan hit out after Mr Mandelson condemned Labour leader Ed Miliband's plans to enforce a 18-month freeze on bills, saying the party was "in danger of being taken backwards."

Mr Sheridan - also chair of the Unite union parliamentary group - lambasted the Labour peer's decision to attack his own party as an example of "all that is wrong with the Lords."

"The only thing going backwards is people's standard of living," the MP said.

"Our party stands up for ordinary people - those who are struggling to pay soaring energy bills - but all he seems interested in is protecting his financial portfolio in the energy companies."

Lord Mandelson was a member of ex-PM Tony Blair's inner circle and once pronounced that he was "intensely relaxed about people getting filthy rich."

He is also on the books of global consultancy firm Global Counsel. It counts energy as one of its areas of business, although it says it is not linked to big firms in the sector in Britain.

The peer also has a number of other ties to energy firms, including as chairman of investment bank Lazard International.

Mr Sheridan said: "Mandelson's attack just typifies how out of touch he is on this.

"Like many in the Lords he has become part of the establishment and is using his links within the Labour Party as an extension of his outside earnings.

"These people have made a good living out of the Labour Party but have left those who supported them behind."

Mandelson has been among right-wing Labour figures linked to the Progress faction - funded by billionaire Lord Sainsbury - who have hit out at union involvement in the party.

He told a Progress conference in May that trade unions wielded a "disgraceful" influence.

The faction once ruled the party with an iron fist but fears that it is being pushed out of its position of power under Mr Miliband's leadership.