A vehicle immobilisation device (60) is provided for securing to a vehicle windscreen, comprising screening means (46a; 46b) which is changeable from a first, more compact configuration to a second configuration and which, when the device is in an in-use disposition on the vehicle windscreen, serves to impair a driver's view through the windscreen. Suction grip means (40a; 40b) are provided for holding said screening means in the in-use disposition on the windscreen by suction. Release means (51) are also provided to enable release of the suction of said suction grip means so as to allow removal of the device from the windscreen.