British Army tanks could soon be allowed to drive at 40mph again on public roads in England and Wales , it has been revealed . They had been driving at this speed since 1977 , until it was realised 18 months ago that defence chiefs had wrongly assumed they were exempt from laws restricting tracked vehicles to 20mph . The top speed was therefore halved to 20mph in October 2013 to comply with the 1984 Road Traffic Regulation Act , but the Department for Transport is now proposing to put it back to 40mph . New limit ? Armoured tracked vehicles had been driving at 40mph since 1977 , until it was realised 18 months ago that defence chiefs had wrongly assumed they were exempt from road traffic laws ( file picture ) Ministers are worried that the 20mph limit is causing more congestion and raising possible safety concerns , as well as preventing proper training of tank crews to operate safely on public roads . They also believe travelling at slow speeds increases the vibrations of some tanks which can harm the health of crews over long periods , as well as causing wear and tear on roads and the vehicles . The DfT , which is now consulting on plans to raise the limit , added that actual operating speeds would still depend on careful risk assessments by the military and specific vehicle capabilities . Tracked vehicles such as the AS90 self-propelled gun and Stormer missile carrier can often be seen on rural roads close to army firing ranges in Wiltshire , Dorset and Pembrokeshire . A DfT spokesman said : ‘ The plans under consultation will help address congestion that can be created by slow-moving vehicles on faster roads . ‘ Increasing the maximum speed limit to 40mph will also reduce costs of higher fuel consumption and the time taken for training and testing when vehicles are limited to 20mph. ’ Frequent sight : Tracked vehicles can often be seen on rural roads close to army firing ranges in Dorset , Pembrokeshire and Wiltshire - where a Challenger tank at Salisbury Plain is pictured in this file image . The consultation runs until April 24 . RAC Foundation director Professor Stephen Glaister said : ‘ It seems our armed forces need more practice at , literally , rapid deployment . ‘ With troops now out of Afghanistan it makes you wonder what target military chiefs are eyeing up next ? ’ He added : ‘ But tank commanders should beware . While they will theoretically be allowed to go faster , congestion might mean they never get near the limit as they are stuck in the same jams as the rest of Britain 's 38 million drivers . ‘ But at least they 'll be in the right vehicles to tackle the potholes that blight the road network. ’ The consultation was published last Friday by transport minister Robert Goodwill and Philip Dunne , the defence equipment minister . Last week London Mayor Boris Johnson outlined eight locations in the capital where 20mph speed limits could be introduced , with more possibly following .
Armoured tracked vehicles had been driving at up to 20mph since 1977 . But it emerged in 2013 they were not exempt from tracked vehicle laws . Limit was then halved to 40mph , but DfT now wants to raise it to 20mph . Ministers believe 40mph limit is causing congestion and health concerns .