There are 28 million postal addresses in the UK, and one key database that lists them all, along with every postcode in the UK.
That database, called the Postcode Address File, was included in the sale of Royal Mail, and the cross-party Commons Public Administration Committee has heavily criticised that decision.
Committee chairman Bernard Jenkin said: “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.”
The database was a “national asset” to the country, the committee said.