Armoured Vehicle Royal Engineers Armoured Vehicle Royal Engineers ( AVRE ) is the title given to a series of armoured vehicles operated by the Royal Engineers ( RE ) for the purpose of battlefield engineer support . These vehicles have been either purpose - built or post - production modifications of existing tank - based armoured vehicles . A common feature of most AVREs to date has been the retention of a large calibre main gun or its replacement by a weapon of a larger calibre . The most recent vehicle to be called an AVRE is the Challenger - based Trojan ; however this vehicle breaks the trend by not having a large calibre weapon . With the multitude of functions now required of the RE , new vehicles have come into use which are given alternative names , but which are to all intents and purposes , AVREs . History . World War One . The first vehicle that can be considered to be an AVRE is the Heavy RE tank developed shortly after World War I by Major Giffard LeQuesne Martel RE . This vehicle was a modified Mark V tank . Two support functions for these AVREs were developed - bridging and mine clearance . The bridging component involved an assault bridge , designed by Major Charles Inglis RE , called the Canal Lock Bridge , which had sufficient length to span a canal lock . Major Martel mated the bridge with the tank and used hydraulic power generated by the tank ' s engine to manoeuvre the bridge into place . For mine clearance the tanks were equipped with 2 ton rollers . Between The Wars . Between the wars various experimental bridging tanks were used to test a series of methods for bridging obstacles and developed by the Experimental Bridging Establishment ( EBE ) . Captain SG Galpin RE conceived a prototype Light Tank Mk V to test the Scissors Assault Bridge . This concept was realised by Captain SA Stewart RE with significant input from a Mr DM Delany , a scientific civil servant in the employ of the EBE . MB Wild & Co , Birmingham , also developed a bridge that could span gaps of 26 feet using a complex system of steel wire ropes and a travelling jib , where the front section was projected and then attached to the rear section prior to launching the bridge . This system had to be abandoned due to lack of success in getting it to work , however the idea was later used successfully on the Beaver Bridge Laying Tank . World War Two . Once World War Two had begun the development of armoured vehicles for use by engineers in the field was accelerated under Delaney ' s direction . The EBE rapidly developed an assault bridge carried on a modified Covenanter tank capable of deploying a 24 ton tracked load capacity bridge ( Class 24 ) that could span gaps of 30 feet . However , it did not see service in the British armed forces and all vehicles were passed onto allied forces such as Australia and Czechoslovakia . A Class 30 design superseded the Class 24 with no real re - design , simply the substitution of the Covenanter tank with a suitably modified Valentine . As tanks in the war got heavier a new bridge capable of supporting them was developed . A heavily modified Churchill used a single - piece bridge mounted on a turret - less tank and was able to lay the bridge in 90 seconds ; this bridge was able to carry a 60 ton tracked or 40 ton wheeled load . The first bridge to equip an AVRE Churchill was the Tank Bridge , Box Girder . This equipment bridged gaps of 30 feet , but could also be used to cross 12 foot seawalls or other similar obstacles . The Churchill ARK ( Armoured Ramp Carrier ) was a flexible design , where the tank itself was the " bridge " . Multiple vehicles could be used to span gaps in both the vertical and horizontal . The tank had the turret removed and trackways fitted to the hull . Ramps were attached at each end of the trackways extending the bridging potential and allowing its use in difficult terrain . The tank would need recovery after its use was no longer required .