FAST trains out of Euston calling at Harrow and Wealdstone station have been delayed or cancelled this afternoon.

Overhead line problems at Hemel Hempstead in Hertfordshire have forced services to Birmingham New Street - run by Virgin Trains - and London Midland's service to Tring to be scrapped as far ahead as 1.20pm.

Southern trains between East Croydon and Milton Keynes are only going as far north as Watford Junction.

London Overground stopper trains remain unaffected while the National Rail Enquiries website says customers can expect delays of up to an hour.