A motorist who put cooking oil in his car's brake fluid has been given a suspended jail sentence and banned from driving by Swansea Crown Court.
Williams' 'death trap' car was confiscated by the judge
David Wyn Williams, 25, already has a conviction for using a rolled-up carpet as a bumper on his old Rover.
The unemployed chef from Borth, Ceredigion, who admitted dangerous driving, was carrying four children when stopped about a faulty light.
His barrister said the offence came "out of ignorance and stupidity".
Williams was stopped in his P-registration car driving up Penglais Hill, Aberystwyth.
The court heard that the police officer panicked as the car rolled backwards as soon as he released the handbrake.
He pumped the foot brake 10 times with "no effect whatsoever," said Sarah Lambert, prosecuting.
Miss Lambert said a consultant engineer found the brake fluid reservoir was full but the liquid inside was a strange colour and had congealed into "a globular, jelly-like substance."
Williams confessed he had added vegetable oil.
She told the court that Williams relied on the handbrake and the gears to slow the car.
He had four girls in the car at the time, all of them aged under 16.
Miss Lambert said Williams claimed the foot brake "was a bit spongy" after work had been carried out on the vehicle at the local branch of ATS.
Police seized the car and later checked his story, finding he had admitted to staff at ATS he put vegetable oil in his brake fluid.
More checks found two of the vehicle's doors would not open - one did not even have a handle - a tyre was bald and there was no rear-view mirror.
The court was told that Williams had already been warned by a mechanic the car was unsafe.
Williams was jailed for six months, suspended for two years, and banned from driving for 12 months.
He was ordered to pay £230 in court costs and to take an extended driving test before having his licence back.
The judge, Mr Recorder Nicholas Gareth Jones, ordered the car to be confiscated.
"It would cost more to put it right than it is worth," he said.
"It was a death trap and the consequences could have been very serious if not tragic.
"You are very lucky not to be here on a far more serious charge. You posed a very serious risk to yourself, your passengers and to other road users."
Williams' barrister, Craig Jones, said, "He now understands the risk he posed.
"He has an interest in cars but it exceeds his knowledge. He takes a rather immature attitude towards cars.
"The offence was out of ignorance and stupidity."
Williams, he added, would be taking the bus in future.