Ambulance chiefs are investigating why it took a crew more than an hour to reach a woman badly injured in the Easter Sunday disturbances in Bradford.

Julie Cook, 39, blundered accidentally into the middle of the trouble after leaving her sister's home in Allerton.

She was hit full in the face by a brick hurled through the side window of her car at the junction of Great Horton Road and Horton Grange Road as she tried to find her way out of the city.

Despite horrific injuries, she managed to escape the scene and pulled over to dial 999 on her mobile phone.

But it was more than an hour later before an ambulance arrived, and even then it had to be flagged down by helpers. It was not the one that had been despatched to rescue her.

She is now questioning why an ambulance was not sent immediately to her aid - even if it had to come under police guard.

Police did provide an escort to fire crews as they battled to put out flames at a pharmacy in Horton Grange Road that night.

Miss Cook's injuries were so serious that she later needed a seven-hour operation to reconstruct her shattered cheekbone, nose and brow.

"I pay my taxes for a service and that service wasn't forthcoming, and I am really upset about that," said Miss Cook, an occupational health nurse who lives in Derbyshire.

"I understand how the ambulance service would not want their staff put in jeopardy, but no one's explained the whys and wherefores of what happened to me and it would be good to have an explanation."

She said she was attacked at 11pm and phoned immediately for an ambulance from her car in Great Horton Road. When it did not arrive, her sister Jane, of Allerton, where she had spent the evening, also rang to chase it up.

But it was only when a group of young Asian men, who were comforting and protecting Julie, flagged down another ambulance that she got help - eventually arriving at Bradford Royal Infirmary at 12.30am.

A WYMAS spokesman said a crew was prevented from reaching Julie because the area was too dangerous.

"We had not received confirmation that it was safe to proceed to the incident, and an earlier ambulance had been approached by people carrying petrol cans who asked it to proceed into an unsafe area," the spokesman said.

"We understand the concerns of Julie Cook, and wish her a speedy recovery. We are currently undertaking an investigation into the events of that night, and until that is complete, it is not appropriate to release any more details.

"We strive to work closely with all organisations at the scene of incidents like this in Bradford.

"This is to ensure that our staff are protected, as they carry out their duties as safely and quickly as possible, in what are very difficult circumstances. We look for advice with regard to safe areas, and rendezvous points, and are in constant contact with police, fire and other emergency services at the scene.

"We will discuss the results of our investigation with Julie Cook, should she so wish."

A police spokesman said: "Where possible police, in conjunction with the ambulance service, ensured that the ambulance service didn't go into trouble spots until it was safe to do so.

"We sympathise with the traumatic situation Julie Cook found herself in but we have a duty to protect not only the public but other emergency services staff.

"We have had talks with the ambulance service about the series of events on the night and, as in all serious incidents, we do constantly review the command and control of such incidents and this will happen in this case."