BUSINESS Secretary Vince Cable was accused of overseeing a Royal Mail “cover-up” yesterday after a government-commissioned report exonerated him over the shameful privatisation of Britain’s postal service.

Former City minister and business darling Lord Paul Myners found that the government could have raised an extra £180 million — but said that raising the asking price would have “come with added uncertainty and risk.”

The Commons business select committee said in July that the taxpayer lost a whopping £1 billion in the sale.

The report said that Royal Mail had been undervalued partly due to the behaviour of so-called “pilot fish” investors, who were told that their investments would be prioritised in return for the expertise they could bring.

This led to them making low offers, the report said, prompting ministers to fear a higher share price would not produce solid investments.

Lord Myners repeatedly blamed trade unions for creating uncertainty over share value through the threat of industrial action.

Investment group Lazard, which advised Whitehall that rising the share price would deter investment while given priority investor status, was cleared of impropriety.

But postal workers’ union CWU general secretary Billy Hayes poured scorn on the peer’s conclusion that the share price was set at the right price.

“Vince Cable appointed Lord Myners to mark his homework and unsurprisingly he’s endorsed the government’s actions,” he said, adding: “As we anticipated from a government-commissioned report on privatisation of Royal Mail, it’s a cover-up.”

Mr Hayes pointed to soaring first-day share prices as evidence that the sale was undervalued.

“We wholeheartedly reject Vince Cable’s assertion that Royal Mail had to be sold to raise investment,” he said.

“The company was profitable before privatisation, making £440m last year.”

But Labour shadow business secretary Chuka Umunna took the report as confirmation that the taxpayer had been “disgracefully short changed” by the privatisation.

“In spite of (the limitation of the report’s scope), Lord Myners and his panel still conclude the taxpayer could have missed out to the tune of many millions of pounds,” said the rightwinger.