All trains on a Watford railway have been cancelled for hours as commuters face rush hour chaos.

There is currently no service on the Abbey line between Watford Junction and St Albans due to a “fault on a train”, according to National Rail.

The disruption was first reported at 7.10am and is expected until 10am.

Update: the disruption cleared up by around 12.30pm.

The railways operator said that trains will be cancelled as a result and its online departures board shows there are no services between the towns for the next two hours at least.

In its announcement, London Northwestern railway said the disruption was down to a "broken down unit" and that it hoped the service would recover by 9.45am.

A rail replacement bus is operating in both directions and commuters can also use their ticket at no extra cost on the 321 Arriva bus between Watford Junction and St Albans Abbey.

It comes as the London Overground services from Watford are also closed for six days until Thursday (August 8) to allow engineers to update “life-expired” equipment that is prone to failure.

A 16-mile stretch of railway will see £2million worth of improvements, between Queen’s Park and Harrow & Wealdstone on the Bakerloo as well as between Euston and Watford Junction on the Overground.