The sale of a valuable database as part of the Royal Mail privatisation is fiercely criticised by MPs today - who argue a "national asset" has been lost.
Ministers come under fire for including the the Postcode Address File (PAF), containing 1.8m postcodes and 28m postal addresses, to boost the share price.
The Conservative-led Public Administration Select Committee (PASC) says the move flew in the face of the government's supposed commitment to 'open data', freely available to all for the widest benefit of the economy.
The decision is described as an "unacceptable and unnecessary consequence of privatisation", which could hold back economic innovation and growth. Ministers are urged to avoid a repeat by bringing forward legislation to give the public a 'right to data', in the same way as freedom of information laws.
The PASC's report on Statistics and Open Data, published today, argues this law should create a presumption that restrictions on government data releases should be abolished
Bernard Jenkin, the committee's Tory chairman said: "There is much to be gained from open data, but the government's direction of travel is not clear. The UK Government was an early mover on government open data, but other governments, watching the UK with interest, are catching up fast.
“If the government does not take the opportunities offered, there is a risk in the UK that businesses with growth potential will be deterred by fees for data, and by legal and administrative barriers, while other countries are developing their data industrial base and stealing a lead over the UK."
And, on the Royal Mail decision, Jenkin added: "The sale of the PAF with the Royal Mail was a mistake. Public access to public sector data must never be sold or given away again. This type of information, like census information and many other data sets, is very expensive to collect and collate into useable form, but it also has huge potential value to the economy and society as a whole if it is kept as an open, public good."
Open data is accessible to all, free of restrictions on use or redistribution, and is digital and machine-readable so that it can be combined with other data.
Today's report also cast doubt on the government's pledge that the public would use access to data to hold the public sector to account, warning: "There is no sign of the promised emergence of an army of armchair auditors."
But the Department for Business, Innovation and Skills defended the inclusion of the PAF in the Royal Mail flotation.
A spokesman said: "The Postcode Address File was included in the sale of Royal Mail because it is an integral part of its operations, not to boost the price. While ensuring that PAF remains in Royal Mail's ownership, we are confident that we have secured benefits for data users including free look-ups that will open up new opportunities for growth."