A burglary suspect evaded police after running onto train tracks on the border of Whitton and Hanworth last night, it is understood.
Police began chasing the man, believed to have been wanted for burglary, on foot in Nelson Road, Whitton, at 8.26pm last night.
A spokesman for the Met Police said the man was believed to have run onto the railways tracks, causing trains in the area to be put on alert, and one service to be stopped.
A police helicopter was called in and spent at least 20 minutes hovering over the area, to the south of Hounslow Heath.
British Transport Police also joined the manhunt, bringing in a police dog to aid the search, but a Met spokesman said the man had managed to make off.