City Minister Lord Myners joined calls for an overhaul of the City takeover code in the wake of the Cadbury deal.

The financial services secretary said takeovers “frequently fail to deliver on promises and allow no voice for other stakeholders, including employees and key customers and suppliers”.

His comments came as it emerged that a complaint against Kraft was lodged with the City takeover panel alleging the US group misled Cadbury employees and investors during its battle for the Dairy Milk maker.

A local campaigner and Conservative party candidate wrote to the panel complaining that they believe Kraft breached takeover rules when it pledged to keep the Somerdale factory open near Bath, only to change its mind soon after the £11.5 billion Cadbury deal was completed.

The US food giant attracted strong criticism over the Somerdale decision, with the factory now set to close with the loss of hundreds of jobs.

It is thought that the takeover panel launched an inquiry into the Kraft takeover following the complaint to examine comments made by Kraft executives during the buyout.

Kraft officials said in initial approaches to Cadbury that the group “believes it will be in a position to continue to operate the Somerdale facility”, despite the UK firm’s plans to move production to Poland.

However, in February the US firm announced that the plant would shut by 2011, less than a month after winning a bitter five-month tussle with Cadbury.

In a speech to the Smith Institute last night, Lord Myners welcomed news last month of a consultation to review the code.

However, he said there should also be a requirement for shareholders and not just the board of directors in bidding companies to have access to independent advice to make up their minds on any bid.

He added: “But ultimately the call for change will not come from the Government.

“The owners of firms that have lost so much from ill-advised takeovers must generate the momentum for reform.”

His comments echo the sentiment of a speech made by Business Secretary Lord Mandelson last week in which he asked for takeover rules to be changed to benefit companies’ workforces rather than short-term City speculators following the Cadbury sale.

Lord Mandelson said directors should act more like “stewards” looking after their company’s long-term interests rather than “auctioneers” selling to the highest bidder.

There was public anger that the Government had no powers to block the Cadbury acquisition or to demand commitments from Kraft on UK jobs.

The complaint to the takeover panel was made by Amoree Radford, who heads up the Save Cadbury’s campaign to preserve Keynsham’s chocolate factory, and local Tory candidate Jacob Rees-Mogg.

They allege in the letter that Kraft did not adhere to UK regulations requiring firms to prepare statements with the highest degree of care and accuracy.

The letter states: “The speed with which the closure was announced indicates that the stated intention to keep the factory open was either made without due care or was knowingly inaccurate.

“It is our view that this type of behaviour discredits the City, undermines confidence in financial markets and deserves stern disciplinary action.”

The takeover panel declined to comment and Kraft was not immediately available for comment.

News of the complaint comes as Cadbury shares officially delisted from the London Stock Exchange after the takeover was sealed on February 2.

Kraft’s purchase of Cadbury continued to attract controversy, particularly on the subject of UK jobs.

The Business Select Committee will question Kraft executives later this month on the company’s future plans.

Last month the US firm said it was “unrealistic” to reverse Cadbury’s plans to shut the Somerdale factory.

It said Cadbury had already spent £100 million on building new facilities in Poland and most production would be transferred by the middle of this year.

And this month Kraft further drew the fire of UK unions when it announced its first job cuts within weeks of the takeover.

Up to 150 jobs are threatened at Cadbury’s offices in Uxbridge, west London, and Bournville in Birmingham as Kraft looks to cut out duplications in its newly enlarged operations.

Products manufactured at the Somerdale site include Fry’s Chocolate Cream, the Double Decker, Dairy Milk, Chocolate Buttons, Creme Eggs and Mini Eggs, Cadbury’s Fudge, Chomp and the Crunchie.

Jennie Formby, Unite national officer for food and drink, said: “Unite firmly believes that in making the apparent promises that they did over Somerdale, Kraft breached the high standards of integrity required by the takeover code and as a result Unite has made representations to the takeover panel giving details of where we believe the code has been breached.

“We very much hope that a thorough investigation will take place but will have to await an announcement from the panel as to what the next steps are likely to be.”