Courtney Joy Trueman, who was three months old, died on Saturday after being left in a car outside her home in Dukinfield, Greater Manchester, as temperatures soared to 23ºC (73°F).

Opening and adjourning an inquest at Stockport, Tameside coroner John Pollard said: "I would ask all parents never ever to leave young children in a car, particularly an unventilated one which becomes hot and stifling in a short period of time."

Greater Manchester police are continuing their inquiries into the death of Courtney and are planning to interview her parents Andrew, 29, and Marie, 31.

In car for nearly two hours

Mr Pollard said it was believed Courtney had been left in the car at about 1300 BST and taken to Tameside General Hospital at 1450 BST.

He said paramedics who'd arrived at the scene after receiving a 999 call had been unable to resuscitate Courtney.

Tameside pathologist Dr John Rutherford has been unable to establish a definite cause of death.

Mr Pollard adjourned the inquest, to a date to be set later, for more evidence to be gathered.

Cars 'like glasshouses'

Motoring organisations and charities have warned that in-car temperatures can rise to "terrifying levels" in hot weather.

The Automobile Association is currently carrying out tests on temperatures inside cars at different times of the day.

A spokesman said one result from earlier this month was that on a day when the outside temperature had been 31°C (88°F), it had soared to 56°C (133°F) inside the car.

Even when the temperature outside had dropped to 27°C (81°F), the heat inside the car had continued rising, to 58°C (136°F).

"The car acts like a radiator, continuing to heat up, and we do see some incredible temperatures inside cars. For a child or pet inside, it would be like sitting in a glasshouse," the spokesman said.

A spokeswoman for the Royal Society for the Prevention of Accidents said: "Never leave a young child unattended anywhere. It only takes a minute for something to happen."