A woman aged 94 could lose her right leg after being struck by a mobility scooter in a pedestrian precinct.
Margaret Quarrell's limb is so badly shattered that doctors have warned her family that it may have to be amputated.
The machine landed on top of the pensioner, sending her walking frame flying through the air.
She was pinned to the pavement with the rider still in his seat and passers-by only saved her from being crushed by lifting the scooter off her body.
Mrs Quarrell - a widow who lives alone - is expected to be in hospital for at least three months.
Speaking from her bed in Barking Hospital, Essex, she said: "He arrived from nowhere. It was like being hit by a bulldozer.
"One minute I was coming out of the baker's and going to find my daughter, the next I was hit from behind. I flew one way and my walking frame went the other way."
The police wrongly refused to treat the collision as a road accident, saying scooters are not classed as vehicles as they are not registered at the Driver and Vehicle Licensing Agency (DVLA).
Officers even warned Mrs Quarrell's relatives that any attempt to have the rider arrested could amount to an infringement of his rights.
It was only after the intervention of this newspaper last Friday - when we pointed out to the police that all mobility scooters which use the public highway and can do more than 4mph should be registered - that officers visited Mrs Quarrell in hospital for the first time and took her statement.
Her daughter, Carol Corrigan, said: "I don't think we would have got this far without The Mail on Sunday."
The incident highlights the dangerous confusion over the legal status of mobility scooters, which have a top speed of 8mph.
Last November we reported how many of Britain's 250,000 owners are breaking the law by failing to register with the DVLA.
Mrs Quarrell was struck from behind two days before Christmas as she shopped in Barking.
Store manager Lesley Bownes, 51, who saw the collision, said: "The driver was going much too fast. I've seen him before - he parks outside my shop and walks in without sticks or crutches, carries his shopping to the scooter and then off he goes. He doesn't look disabled to me. And he certainly isn't very old."
Mrs Quarrell was taken to hospital by ambulance but the police said they could do nothing.
Carol said: "They took my mother's name but didn't ask for a description of the man. They said, 'You do realise, he hasn't committed a criminal offence?'
"They said mobility scooters were not covered by the Road Traffic Act and were not registered at DVLA."
A Scotland Yard spokesman said: "This is a grey area because there is no specific legislation covering mobility scooters. If they were registered with DVLA, this incident would be classed as a traffic offence."
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