Railway vandals are being watched by a 'spy in the sky' during the school summer holidays.

Railtrack and British Transport Police launched a helicopter on Monday which will be able to direct instant response units on the ground. The campaign, codenamed Operation Scarecrow, is aimed at combating crime on Britain's railways. Currently, trespass and vandalism costs the industry more than £26æmillion per year. The helicopter, fitted with a thermal imaging camera, will patrol north London.