A law that forces new electric vehicles to have a noise-emitting device has been branded a ‘failure’ by a top car safety expert.

The EU rule, which came into force in July, requires vehicles to emit noise when reversing or travelling below 12 mph. This means Acoustic Vehicle Alert Systems (AVAS) will need to be installed in new models of hybrid and electric vehicles registered after September 1, 2019 – and all new vehicles registered after September 2021.

The law has been put in place to protect pedestrians – particularly children and the disabled – as they struggle to hear silent electric vehicles at low speeds.

But it fails tackle the thousands of dangerous vehicles already on Britain’s streets, according to a warning from Chris Hanson-Abbott OBE, of road safety device manufacturer Brigade Electronics.

“While this legislation is a step in the right direction, it does nothing to stop these existing silent killers and is therefore a failure and a missed opportunity to protect pedestrians,” he said. “And it does not consider the vehicles which don’t fall under the legislation but will be in existence by 2021 and beyond.

“Dangerously quiet electric and hybrid cars will still be on British streets putting vulnerable pedestrians – particularly kids and people who are blind or partially-sighted – in danger.

“The government must step in and force drivers of existing electric vehicles to install noise-generating technology.”

Research by Guide Dogs for The Blind showed electric vehicles are about 40 per cent more likely to hit a pedestrian than a petrol or diesel vehicle. And the average person struggles to hear electric and hybrid vehicles approach at speeds of up to 20 kmh (12.5 mph).

The issue was recently brought into stark relief by figures showing pedestrians are most likely to be hit by a bus in London. Transport for London’s (TfL) stats reveal 38.3 per cent of collisions are with pedestrians.