However on Thursday the government launched a review of the bookbuilding process used to collect orders for shares in such sell-offs. Over the next six years, ministers want to raise 20 billion pounds from the sale of public assets such as stakes in the Eurostar rail link, Royal Bank of Scotland and Lloyds.
Labour said the committee's report backed up their argument that the sale had been mishandled, and that the review of the privatization process was effectively an admission from the government that it had sold the firm too cheaply.
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It had previously seized upon the flotation, and the quick profits made by big banks and City investors, to reinforce one of its central arguments ahead of next year's general election - that Conservative Prime Minister David Cameron's government is out of touch with ordinary voters.
The committee report's criticism focused on the actions of the government, its independent adviser Lazard, and the two banks it hired to lead the sale of shares, UBS and Goldman Sachs.
The committee said the bookbuilding process had been carried out by the advisers in a way that meant investors did not have to reveal the maximum price they would be prepared to pay for the shares. As a result, taxpayers had missed out, they said.
While it found no evidence of impropriety by the advisers, the report criticized the fact that a separate asset management unit of Lazard had been among those granted preferential status in the allocation of shares. It also highlighted that UBS and Goldman Sachs would earn fees from trading Royal Mail shares on behalf of preferred investors, many of whom were their clients.
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"It is clear to us that any perception of financial advantage must be removed from the privatization process," the report said
"Therefore we recommend that the department give serious consideration to excluding any company involved in the selection of preferred investors, as a preferred investor."
Lazard, UBS and Goldman Sachs declined to comment.
The report also said that the government had put too much emphasis on the risk of strikes by Royal Mail staff, resulting in a share price that was too low. It criticised the decision not to raise the price once it became clear demand was high.