All lines are blocked between Watford Junction and London Euston following a signal failure.

London Northwestern Railway says that its tickets are being accepted on London Overground, Underground, and Chiltern Railway services via any reasonable route.

Tickets are also being accepted on East Midlands trains in both directions between Wellingborough, Bedord, Luton, and London St Pancras, and on Virgin Trains.

Road transport has been requested to run between Watford Junction and Watford Met tube station.

Fans heading to Milton Keynes for the clash against Tottenham Hotspur may be affected.

The problem appears to be in the Wembley area.

National Rail says disruption is expected until at least 6pm.