A four-month-old baby boy died and his mother was seriously injured in a road crash.

The boy's father and another couple and their two-and-a-half month old daughter escaped with minor injuries after their car overturned near Warninglid.

They were taken to the Princess Royal Hospital in Haywards Heath where the mother was still being treated last night.

The families, from east London, were travelling home from a trip to the coast in their Toyota car on the northbound A23 when the accident happened.

No other vehicles were involved.

The road was closed for three hours while crash investigators examined the scene, causing tailbacks on the busy road.

Police are still trying to work out how the car ended up on its roof shortly before 7.20pm on Saturday.

Officers appealed for witnesses to come forward.