A Network Rail spokesperson said: “A fire overnight at a timber yard in Harrow has damaged a trackside retaining wall. It will need to be dismantled, made safe and rebuilt. This is a big job expected to take all day. The West Coast main line will remain shut between Euston and Milton Keynes while these repairs are made.
“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. They will be diverted on alternative routes.”