A woman on her way to work along Kent's M20 was stopped by a police car with a blue flashing light.

It was 4.30am and Claire Mobbs, 32, who was alone in her car, began shaking - even though she had been doing 75 mph along the london-bound carriageway.

She pulled over between junctions nine and eight and stopped on the hard shoulder and was then confronted by an undercover cop.

He told her: "Do you know why I stopped you? You were speeding. I am an undercover police officer on my way to work. I was watching you because you were speeding."

But Canterbury Crown Court heard that Mark Downes, 24, was not only a bogus officer - he was also a banned driver!

He would claim he had bought the blue light on the Internet - and had stopped Ms Mobbs because he objected to speeding motorists.

But a judge ruled he had targeted a lone woman in a car - and jailed him for four months.

Downes, of Lascelles Road, Dover admitted impersonating a police officer, two frauds - including getting insurance and a job claiming he had a driving licence, driving while disqualified and dishonestly applying for a Blue Disabled Badge.

By a stroke of luck, Ms Mobbs brother had been travelling to work with a friend in his van in March and had stopped to confront Downes, who then fled away in his car.

Prosecutor Wendy Hewitt said: "Claire Mobbs had been on her way to work along the M20 heading towards London when she noticed a Mondeo in the right-hand lane, dropping back and then pulling towards the side of her.

"She thought he was trying to tell her that she had done something wrong but she didn't want to look at the driver. After a while the Mondeo drove off at speed.

"She then noticed a blue flashing light coming from the vehicle behind her and she became frightened and started to shake, and began wondering what she had done wrong.

"She thought it was the police and pulled over to the hard shoulder and realised that it was the Mondeo she had seen earlier. She thought she was in trouble for not stopping earlier on. She stayed in her vehicle."

She said he was convincing and she believed that he was a police officer and kept on apologising.

It was then her brother and his friend who came to her aid - and realised "instantly" that the sinister Downes was a fake.

They challenged him to show a police badge - forcing him to panic and drive away, she said.

"The Crown say not only was this misrepresentation but that there was a blue light in the car and he had stopped a female travelling alone at 4.30am, " she said.

Ex-soldier Downes would later claim he had stopped Ms Mobbs because he objected to people speeding.

His barrister Alice Dobbie asked the judge to accept he had not targeted Ms Mobbs or that there was "anything overtly sexual about it."

But Judge Nigel Van Der Bijl said: "You are not likely to stop a fully-grown man aged between 25 and 30. I take the view that you targeted a lone woman on the motorway early in the morning...to make you feel and look big."

Downes was also banned from driving for a year and ordered to take an extended driving test before re-applying for a licence.