Police made an arrest on suspicion of drug possession after reports of a “man on the tracks” caused delays.

Thameslink said that emergency services were called to Radlett station, near Watling Street, just before 5pm last Thursday (June 15), adding that police removed and detained a trespasser by 5.17pm.

British Transport Police later confirmed that a man in his forties was arrested on suspicion of trespass and a possession of a class B drug.

He has been bailed pending further enquiries.

Passengers heading towards Luton Airport reported being stuck in Elstree with no indication of when they would be able to start moving again.

The 3.19pm Sutton to St Albans City train was initially delayed and then caused further delays to services behind it.

National Rail added that some late running trains may have been forced to call at fewer stops.

Hertfordshire Constabulary were also called to the scene, although British Transport Police were leading.