The infrastructure bill includes measures to change the Highways Agency from a public entity, accountable to government ministers, into a publicly owned company.

Parmjit Dhanda, Prospect’s parliamentary officer, said: “We are very concerned that the Highways Agency is being prepared for a full-scale privatisation. Both Prospect and the House of Commons transport select committee have warned of the dangers of this.

“Successive government reviews have concluded that the Highways Agency is efficient but could be improved. We do not believe that reducing its accountability to government and the public is the answer.

“Moving towards a private model will open the door to levying tolls to generate income. The agency could achieve greater efficiency if it was sure of its longer-term funding agreements. As we now have five-year, fixed-term Parliaments, longer-term funding stability is possible.”

In October 2013, the Department for Transport announced a pilot project to place sensors along a 50-mile stretch of the A14 to create a ‘smart road’ that can monitor traffic by sending signals to and from mobile phones in moving vehicles.

The Guardian newspaper said this was a first step to building the infrastructure for charging. In 2007, over 1.8 million people signed a petition against road tolling.

Dhanda added: “A good strategic road network is vitally important to the economy and the way it is managed should have a major impact on meeting targets in the Climate Change Act. It’s unfortunate that the government seems more focused on paving the way for road tolls than reducing car dependency.”