M25 turning 40: Keeping Britain’s busiest motorway moving

“During the festive period we have previously come across presents that have fallen out of car roof boxes and spread across the carriageway,” Martin added.

“Sometimes we have been able to reunite them with owners, but sometimes they’ve ended up under lorry wheels.”

Martin said on other occasions, items including wheelbarrows, bicycles, canoes and even a longbow were found.

Former Prime Minister Margaret Thatcher cut the ribbon to mark the completion of the M25 on 29 October 1986, hailing it as a “magnificent achievement”.

The 117-mile motorway, which runs through Kent, Surrey, Greater London, Buckinghamshire, Hertfordshire and Essex, quickly attracted huge numbers of motorists.

This has led to chronic congestion despite decades of efforts to keep traffic moving, including widening lanes, upgrading junctions and introducing “smart motorways”.