Construction work to convert parts of the A1(M) into a smart motorway in Hertfordshire has been put on hold until a government review is complete.

After smart motorways were linked with an increase in road deaths, transport secretary Grant Shapps said all plans should be put on hold - and Highways England has confirmed this is the case for the A1(M), despite work being due to start in March.

The results of the review are expected to be released soon, although no date has been given.

Highways England's current plan is to turn the A1(M) between Junction 6 for Welwyn and Junction 8 for Stevenage into a smart motorway, meaning the hard shoulder would be used as an extra lane at certain times.

There have been calls to scrap all smart motorways, citing that they are too dangerous - with one concerns emergency refuge areas are not frequent enough.

Welwyn Hatfield MP Grant Shapps spoke to BBC Panorama on the topic: "I think they [emergency refuge areas] are almost certainly in some cases too far apart.

"I think two-and-a-half miles is much too far apart, people need to be passing these every 60 seconds at a normal speed."

The death toll on stretches of smart motorways has reached 38 in the last five years.

He added: "I'm very unhappy about there being so many different types of motorway, I don't think we should continue with dynamic motorways and all lane running and smart motorways it's just too confusing.

"We absolutely have to have these as safe or safer than regular motorways or we shouldn't have them at all."

The Welwyn Hatfield Liberal Democrats had written to Mr Shapps asking him to put the plans on hold until safety issues have been thoroughly reviewed.

Herts county councillor Nigel Quinton said: "Of course we want to see an end to the daily snarl ups on the A1(M), but this cannot be at the expense of safety.

"If we are to have all lanes running then it is vital that there are frequent emergency refuges - these are dangerously far apart on the M25, as the BBC reports highlight."

Highways England is due to hold two events in Stevenage this weekend - in the town centre tomorrow (Saturday) and at Sainsbury's Coreys Mill store in Hitchin Road on Sunday - to publicise the smart motorway plans, with a further date at Welwyn Garden City's Waitrose store on Friday, February 7.