Damage to the tunnel at Watford Junction has caused train chaos with passengers experiencing long delays and cancelled services.

The damage to a section of brickwork at the station has resulted in a 20mph limit for trains on the fast lines approaching Watford.

The temporary restriction, which is likely to be imposed all day, has caused a backlog of services.

Travellers vented their frustration on social media with some complaining their trains had been terminated prematurely or delayed by 30 minutes.

Sam Kelly, spokesman for Network Rail, said: "There was an issue overnight. On a routine inspection it was discovered there was some damage to the brickwork in the tunnel at Watford Junction Station.

"There has been a temporary speed limit of 20mph in place through the tunnel, and it is due to remain in place for the rest of the day.

"We had the engineers out in the early hours of the morning and all four fast lines are open at Watford."