A fourth person has been arrested by officers investigating a stabbing at a Tube station.

Police were called to reports of a serious assault at Seven Sisters station at around 8.45am on Tuesday morning (July 23) .

A man who was found at the scene with injuries consistent with being stabbed was rushed to hospital.

British Transport Police confirmed yesterday (July 25) that he was still in a critical condition.

The force has previously said that a 17-year-old boy was arrested on suspicion of murder.

A second man, aged 24, has now been arrested on suspicion of assisting an offender.

It comes after a woman aged 18 and a girl aged 15 were arrested on suspicion of grievous bodily harm with intent.

The younger teenager has also been arrested on suspicion of common assault.

Any witnesses are urged to contact British Transport Police by calling 0800 405040, or texting 61016, quoting reference 171 of 23 July.

 Alternatively, Crimestoppers can be contacted anonymously by calling 0800 555 111.