A Government programme designed to free up public land for new homes has been criticised for misleading statistics, a lack of monitoring and the absence of any economic rationale.

The damning report from the National Audit Office (NAO) said while on the face of it the Government had met its target to release enough land for up to 100,000 homes by 2015, closer examination revealed fundamental flaws.

Among them were the Department for Communities and Local Government's 'wide interpretation of the land that could be counted towards the target'. This included land for 15,740 homes that had been disposed of before the programme began. A further 10,783 were included despite being on sites owned by the Royal Mail and British Waterways – which have since left the public sector – and have not been developed.

The NAO said it found 'no supporting documentation or economic evidence behind the target [of 100,000 homes] or how it was allocated to departments'.

It also criticised Government departments for not routinely monitoring what happens to land after disposal, claiming it was unclear how many homes have actually been built as a result.

But the NAO said Government had taken action when it became clear progress was too slow and that departments have 'used a range of disposal methods and partnering approaches with developers with the aim of ensuring homes were built and profits shared'.

The public spending watchdog said a new process for land disposals had been introduced this year. It sets a target of delivering at least £5bn of land and property sales over the next five years during which time enough land for 150,000 homes will be released.

The NAO said: 'In taking forward this new target, the DCLG and the Homes and Community Agency should review and share the lessons from this programme, including the need for the department to clarify how it intends to measure progress through sales proceeds or number of potential homes; and for someone to take responsibility for monitoring what happens to land after disposal within the target period.'

A DCLG spokesman said: ‘This was an ambitious programme to release surplus government land to build 100,000 homes to help families achieve their dream of home ownership and we broke our target more than a month early with enough land released to build more than 109,000 new homes.

‘We now want to go further and faster still with land sales for a further 150,000 homes by 2020 whilst protecting taxpayers by cutting the hoarding of vacant public land and disused buildings.

‘We will consider and learn any lessons from the NAO's findings.’