The survey was commissioned by the RAC, which said it “completely undermines” the reason that smart motorways were introduced in the first place – to increase capacity on congested roads.

The research was conducted with 1,904 drivers who have driven on ‘all lane running’ smart motorways.

It found that a fifth (21 per cent) claimed to have frequently steered clear of the left-hand, inside lane, while 28 per cent admitted to doing so occasionally.

A majority of drivers (68 per cent) also said they regularly see motorists using other lanes when the inside lane is free.

Asked why they deliberately avoid driving in lane one, an overwhelming three-quarters (77 per cent) of drivers say they are worried they might encounter a stationary, broken-down vehicle as there is no hard shoulder while 40 per cent are fearful of being crashed into if they had to stop.

The rollout of smart motorways was paused in January by the Department for Transport (DfT) for five years...