Abstract: An immobilizing device 12 is connected to a wheeled vehicle such as a trailer 12 or caravan 52 by a connection. The device 12 comprises a wheel clamp to be secured to or about a wheel 14,53 of the wheeled vehicle. The connection in one embodiment comprises a rod 38 which is slidable and rotatable in two bushes 40 on the chassis 42 of the vehicle 10, the rod 38 being transverse to the vehicle and being connected to a bar 34 which is pivotally connected to the wheel clamp. In another embodiment the connection comprises a rod 70 which is slidable forwards and backwards in relation to the vehicle in two bushes 72 on the vehicle chassis and is connected to the wheel clamp.