Six hundred people have been evacuated from trains after a grass fire next to rail lines in Finchley Road.
A damaged overhead line caused a short circuit, which in turn sparked a grass fire on the railway bank next to it. The London Fire Brigade was called at 2.39pm.
The line affected is the main line route going into King's Cross and St Pancras, which runs next to the O2 Centre. Thameslink services are affected. Speed restrictions are already in place due to soaring temperatures increasing the risk of tracks buckling.
The 187 and 268 buses are also being diverted as a result.
Sainsbury's and Waitrose have provided bottles of water to passengers being taken off the services that have been halted nearby by the blaze.
Fire crews from West Hampstead and Paddington are currently at the scene.
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