A train has derailed near Watford Junction, injuring two passengers and causing major disruption to services in and out of London Euston station.

Operators said the train was struck by another service after hitting the landslide during torrential rain and thunderstorms in the area.

A man was treated for a neck injury and a woman for chest pains, the East of England Ambulance Service said, but their injuries were not believed to be serious.

London Midland said the 6.19am service from Milton Keynes to London Euston came off the track at around 7am.

The landslide near Watford Junction station which has caused a train to be derailed (PA)

"Due to a derailment this morning, there will be delays and cancellations," a spokesperson for the operator said. "Ticket acceptance in place on other train operating companies."

British Transport Police said officers were called to reports of a landslide at the Hunton Bridge Tunnel near Watford and were working with fire and ambulance services at the scene.

Martin Frobisher, the route managing director for Network Rail, said: “A train hit a landslip, caused by torrential rain, resulting in a small section of the train to leave the tracks a few miles north of Watford. The train remained upright.

“Engineers are on site and train services are now running through the area but it will be some time before a normal timetable resumes.

“Our priority is to fully reopen the railway as soon as it is safe to do so. A full investigation into what happened will take place.”

The accident took place around a mile north of Watford Junction station, with a train passing in the other direction colliding with a "glancing blow" shortly afterwards the derailment. It did not leave the tracks.

Train passengers quickly reported hearing announcements saying there had been a landslide.

The landslide near Watford Junction - in pictures Show all 6 1 /6 The landslide near Watford Junction - in pictures The landslide near Watford Junction - in pictures The landslide near Watford Junction station which has caused a train to be derailed PA The landslide near Watford Junction - in pictures Operators said the train was struck by another service after hitting the landslide during torrential rain and thunderstorms in the area PA The landslide near Watford Junction - in pictures British Transport Police said officers were called to reports of a landslide at the Hunton Bridge Tunnel near Watford and were working with fire and ambulance services at the scene PA The landslide near Watford Junction - in pictures There were no reports of any injuries after the 6.19 London Midland service from Milton Keynes to London Euston came off the track at around 7am PA The landslide near Watford Junction - in pictures Workers at the landslide near Watford Junction PA The landslide near Watford Junction - in pictures Workers at the landslide near Watford Junction station which has caused a train to be derailed PA

"The ontrain announcement said landslide and derailment at Watford Junction, not good at all," Rugby Rail Users Group wrote on Twitter, describing trains "stacked" up unable to move.

The town is on a busy commuter line between London Euston and the Midlands, with the majority of services passing down the West Coast Main Line.

A spokesperson for London Midland said the affected section of railway was the busiest for both freight and passenger traffic in Europe.

"We expect disruption until at least lunchtime but it may last longer," he added.

The incident came during heavy rains and thunderstorms in London and much of England following a spell of unseasonably hot weather.

National Rail warned of "major disruption between Milton Keynes Central and London Euston, although two out of four lines in the area were able to reopen.

"Disruption is expected to continue until the end of the day," a spokesperson said, adding that tickets will be accepted on alternative routes.

Virgin Trains customers can use tickets on Chiltern Railways, East Midlands Trains and Virgin Trains East Coast between London Kings Cross and Scotland.