Motorists who drive in closed lanes on smart motorways will soon be liable for an automatic £100 fine and three penalty points.

Police will be given the power to punish drivers caught on traffic cameras ignoring red X signs, under new Home Office legislation being introduced from June 10.

Highways England, which operates England's motorways and major A-roads, said cameras will be used to enforce lane closure offences from "late summer".

Currently motorists who drive in closed lanes are only fined if they are caught by an officer at the time of the offence.

Red Xs are used to indicate when a lane is closed, such as when a vehicle has broken down away from emergency laybys.

Motoring groups have warned that smart motorways create a safety risk as vehicles that break down in live lanes risk being hit from behind.

Highways England has issued more than 180,000 warning letters to drivers who have ignored red X signs since the beginning of 2017.

AA president Edmund King said the use of cameras to catch offenders is a "welcome measure to improve safety".

He said: "Our research shows that one in 20 drivers continue to drive in red X lanes even when they've seen it, and so far Highways England have written warning letters to over 180,000 drivers about their actions.

"Red Xs are put up to warn of an obstruction, so drivers must get out of the lane when they see them.

"We have had several incidents recently where AA members' cars have been hit in a live lane on smart motorways."