The government has endorsed a conspiracy about “15-minute cities” as part of its major policy announcement prioritising car owners – despite having already debunked the theory.

Speaking to the Conservative party conference in Manchester today, transport secretary Mark Harper called himself “proudly pro-car,” while describing the concept of 15-minute cities – where local amenities are located within a 15-minute walk or cycle – as “sinister”.

“What is sinister, and what we shouldn’t tolerate,” said Harper, “is the idea that local councils can decide how often you go to the shops, and that they can ration who uses the roads and when, and that they police it all with CCTV.”

There has been opposition to 15-minute cities from those who say they are a front for “everlasting surveillance” and designed to restrict people’s freedom.

But these theories have been widely debunked, including by the government itself.