Rail travellers into Euston station are facing severe disruption following a fire overnight at a factory and offices in north-west London.
There are currently no services on London Midland and Southern between Milton Keynes Central and Euston.
West Coast Main Line trains from Glasgow and Edinburgh, including the Caledonian Sleeper, into London have been cancelled.
Services to Manchester, Birmingham and Liverpool are also been affected.
Nearly 60 firefighters were called to the blaze in Chantry Place, Harrow, at 23:47 BST on Thursday.
As a result, trains through Headstone Lane have been cancelled.
A shuttle service between Euston and Harrow and Wealdstone is being established to allow services along the west coast to run.
Tickets from affected routes are being accepted on London Buses and Southeastern, Southern and Thameslink services via any reasonable route
London Overground trains between Watford Junction and London Euston are running, but experiencing severe delays.
A spokesperson for Network Rail said: “Passengers wanting to travel on the West Coast Main Line and West London Line are urged to check with their train operator or nationalrail.co.uk before travelling as disruption and cancellations are to be expected throughout the day.”
London Fire Brigade said a warehouse was alight and a cordon was put in place amid fears that propane cylinders might explode.
The fire is now under control, according to the London Fire Brigade, although 12 residents were told to leave properties as a precaution.