Ministers have been accused by a cross-party group of peers of trying to “bury” the results of the biggest ever Whitehall examination of European Union powers, after it found no evidence that the EU was interfering excessively in any aspect of British life.

In a hugely damaging move for the government, the European Union Committee of the House of Lords, chaired by former Tory minister Lord Boswell, comes close to saying that ministers tried to cover up the findings, which do not support David Cameron’s claims that the EU is “becoming a state” and has already accrued excessive powers.

By contrast, the so-called “balance of competences” review – hailed by William Hague in 2012 as the “most extensive analysis of the impact of UK membership of the EU ever undertaken” – found no area with a case for transferring powers back from Brussels.

It is understood that the pro-EU Liberal Democrats are now preparing to launch a stinging attack on their coalition partner for the way it has hidden the review, because its findings were not politically convenient to a Tory party whose whole EU policy is geared to bringing power back from Brussels.

The accusations that the report has been buried will also infuriate the UK’s EU partners and could make the job of renegotiating this country’s terms of membership far more difficult for Cameron, if he wins the election, as it will be known in other European capitals that the London civil service believes there is no real case for repatriating powers.

Commenting on his committee’s highly critical report into the way the government has handled the review, Boswell also tore into it for spending up to £5m on the project, only to make no effort to pull its findings together and make them accessible to a public that wants to know the truth about the UK’s relationship with the EU.

“There is no point spending up to £5m of public money on an excellent review and then burying it. People need to know the facts about the UK-EU relationship,” Boswell said.

He told the Observer that of the 32 reports into different areas of the EU’s operation in the review, there was “no report in which it was demonstrated that too much power resided in Brussels”.

He added: “This was trumpeted as the biggest survey of its kind into the balance of power between the UK and Brussels but, for whatever reason, [ministers] decided not to present a coherent overall view of the work.”

The committee said the entire project was “diminished by the government’s failure to deliver its undertaking in 2012 to draw together the analysis contained in the review”.

Last night, businessmen and former diplomats joined the chorus of criticism, suggesting that the findings had not been promoted because they were inconvenient for the Tory party. Cameron has promised to hold an in/out referendum by the end of 2017, having renegotiated the UK’s terms of membership by repatriating powers.

In his TV interview with Jeremy Paxman on Thursday 26 March, the prime minister said Europe “isn’t working properly”, adding: “The EU is trying to become too much of a state. It’s got too much power. We want to be in Europe for trade. We don’t want to be a part of an ever-closer union.”

Lord Hannay says there is no compelling case for repatriation of powers. Photograph: PHILIP MARK/AP

The Foreign Office said last night the review showed reform was needed to make the EU more accountable.

Lord Hannay, former British ambassador to the EU, who now advises British Influence, a pro-EU campaign, said the information in the review was highly relevant to the general election on 7 May: “The outcome of the government’s meticulous and evidence-based Review of the Balance of Competencies of the EU is one of the best-kept secrets of recent months, largely ignored by the media and seldom mentioned by the government itself. And yet it is a crucial element in the election debate over Britain’s future in the EU.

“The single, clear message from the review is that in none of its 32 chapters is there a compelling case for the repatriation of powers from Brussels to Westminster and Whitehall. So, while the EU needs reform, our relationship with it does not warrant wholesale dismantling.”

Roland Rudd, chairman of Business for New Europe, said: “This important review, which was thorough and comprehensive, showed the overall balance of competences to work well for Britain. Companies across the country told the review how vital it is for them that the UK stay in the EU. For example, easyJet said that it only exists as a company because the EU opened up the aviation market to low-cost providers.

“Eurosceptics hoped that the review would bring forth lots of companies who support their demands for unrealistic repatriation and opt-outs. The fact is that this review was open to anybody to contribute, yet the overwhelming evidence received strongly supported the UK remaining in the EU and that an attempt to radically rewrite the treaties is neither achievable nor desirable.”

• This article was amended on Sunday 29 March to remove a reference to British Influence as a thinktank.