A white van filmed driving erratically as it pursued the terror suspect who ploughed into cyclists and pedestrians is at the centre of growing speculation that the “attacker” was being followed.

As terrorism police and security sources insisted that the 29-year-old motorist arrested at the scene was not known to them or under surveillance at the time, analysis of footage of the “attack” reveals how an unmarked van made a series of extreme manoeuvres to keep up with the suspect.

A 47 second clip of the incident prompted Conservative MP Mark Francois, who served as a minister in the Ministry of Defence, to describe the mystery vehicle’s antics as “classic security” behaviour, similar to that used during surveillance operations.

Detectives have now established that the suspect, understood to be from the West Midlands, drove the Fiesta, which is privately owned and has the registration FL10 CWZ, from Birmingham to London late on Monday night.

From 1.55am to 5.55am it roamed around the West End, including along Tottenham Court Road near Soho, home to many late night clubs, before heading to Whitehall and Westminster at around 6am as the city wakes up.