National Highways is missing its 10-minute target for responding to drivers who break down on smart motorways, almost a year after it was meant to come into force.

Statistics for June, revealed by National Highways chief executive Nick Harris to the Commons Transport Committee on Wednesday, show that traffic officers missed the goal by an average of 18 seconds, and the figure has dropped by six seconds since March.

There have been long-standing fears about the safety of smart motorways, where hard shoulders are used as live lanes after fatal incidents where vehicles stopped in live lanes were hit from behind.

Mr Harris insisted National Highways was making “good progress” despite failing to hit its target every month since it was introduced in July last year.

It comes days after the Office of Rail and Road urged the company to “focus on reducing its response times” to help stranded drivers.

Mr Harris told MPs: “We’re now down to 10.3 minutes for June, so that’s a decrease from May which was 10.45.

“If I go back to March, we got down to 10.2, which is a great achievement… and it compares very favourably with the police whose response is around 15 minutes.

“I’m confident that we’re focused on achieving the 10 minutes this year.”

He blamed “operational reasons” for the rise in response times since March, as National Highways had to “move things around” in the South East.

Sitting next to Mr Harris, transport minister Baroness Vere admitted it would be a “challenge” to convince the public to trust smart motorways.

“You are significantly less safe on a country B-road than you are on pretty much any other road and yet people somehow feel that they are more safe,” she said.

“That the research shows that people are most confident on our most dangerous roads is a challenge.”

An RAC poll of 2,652 UK drivers suggested that 62% believe hard shoulders should be reintroduced across the motorway network.