A large metal structure has fallen on a train carriage carrying passengers in Witham.

Commuters spoke of their fear and described hearing what sounded like an explosion.

The train's pantograph, the metal device on top of the train which links the train and the overhead wires, came crashing through the carriage windows.

Witham commuter Jane Tinkler said:"I was going up to London and all of a sudden at about 8.20am there was a huge explosion.

"I looked out and I could see sparks flying everywhere on top of our carriage, and people onboard and people next to me started screaming.

"You really don't know what is going on and it is really frightening to be in that situation.

"The pantograph, the large metal thing which holds the cables up came crashing down on the train, smashing the windows in our carriage.

"I managed to calm down the people around me as you really do not know what is going on, and that is scary.

"The train just kept moving and about three minutes later we came to a complete stop.

"Then I think it must have burst the water tank or something, as water starts gushing out of the train toilets and coming into the carriage. They stopped this after about ten minutes.

"There was an announcement on the train there had been a fault on the rear end of the carriage, and we hadn't heard anything since.

"The announcement also said there was an engineer on board and they would be on hand to fix the toilet, which they did.

"Everyone has calmed down and they have had time to phone their families and let them know they are OK, there have been no injuries, as far as I can see, but everyone is still shocked.

"Everyone onboard was asked to  move down the carriage as far as possible to hopefully transfer to another train."

A Greater Anglia spokesman said: "I can confirm a pantograph has come down on a train.

"We are investigating the exact cause.

"We apologise to customers for the delay."

Customers in the rear four carriages were moved into the front eight carriages.

The train continued its journey into London.

Greater Anglia advised north Essex commuters not to travel if they can avoid it due to the disruption which is expected to continue.

Disruption is expected until at least 4pm today.