Motorists have been warned to expect a letter through their door if they ignore one important sign on the motorway.

A red X sign will be put over a lane on a motorway when that lane is closed. It is there for your safety and it is illegal to ignore it.

The lane is there for the safety of drivers and passengers. It also provides a safe space for emergency services, recovery operations and road workers.

At times, a red X may be set far in advance of the actual incident.

If you’re caught, you could receive a £100 fine and three points on your licence. In some cases, more severe penalties or a court appearance can be issued.

A spokesperson for National Highways said: “The red X sign is key to supporting safety on motorways. It tells you when a lane is closed, helping any drivers and their passengers who may have got into difficulty.

“It also provides a safe place to work for the emergency services, recovery operators and our road workers.

“Most drivers respect the red X signal. But those who don’t put themselves and other road users at real risk.

“Sometimes a red X signal needs to be set far in advance of an incident to provide access for emergency services. Or to help you re-join the motorway from an emergency area. When you see the Red X, it means the lane is closed and you must not use it.

“Please leave gaps in the traffic to let other drivers move into an open lane.

“Signs will also show when the lane is re-opened. You may see a national or variable speed limit, or a message informing you of the end of the restriction. Do not move into a closed lane even if you’ve passed a hazard, as there may be other hazards up ahead in the same lane.

“If you’re caught, you could receive a fixed penalty of up to £100 and three points, and in some cases more severe penalties or a court appearance.”