UPDATE: Disruption is expected until the end of service. Trains may be delayed by up to 30 minutes with some lines still closed.

The fire brigade is dealing with an incident between London Euston and Watford Junction, which means that all lines are blocked.

The incident is affecting trains between London Euston and Birmingham New Street, Crewe, Holyhead, Liverpool Lime Street, Manchester Piccadilly, Glasgow Central and Edinburgh.

Other services affected are St Albans Abbey, Tring, Milton Keynes, Stratford (London), Gospel Oak, Barking Riverside and East Croydon.

Trains may be cancelled, revised or delayed by up to 40 minutes.

Major disruption is expected until 3 pm.

Operators have ticket acceptance with Chiltern Railways, CrossCountry, Great Western Railway, London North Eastern Railway, Northern, ScotRail, TransPennine Express, East Midlands Railway, London Overground and London Buses.

The latest travel advice is available on the National Rail Enquiries website.