A VIDEO which has been widely circulated online shows the moment a man headbutted a fellow commuter during and argument on the train. 

The incident is understood to have taken place on a train from London to Southend on Wednesday.

Thurrock Gazette:

The video shows the two men - one taller than the other - exchanging words before the taller man appears to heatbutt the shorter man. 

While some fellow passengers are visibly and audibly shocked after the incident, others can be heard laughing at the situation.

A British Transport Police spokesman said: 'British Transport Police received a report at 3.35pm [yesterdaty] of a man fighting and making violent threats to passengers on board a train.

"He was restrained onboard the service and arrested when it arrived at Upminster station.

"Following a search, the man, aged 29, was further arrested on suspicion of carrying a knife and theft by finding. He remains in custody."