Four fire brigades were trying to prevent the flames spreading to other areas of land parched by the intensity of the heatwave of the past few weeks.
The temperature reached 30C (86F) on the hills yesterday and by evening the fire had scorched a large area, causing many families to be evacuated as flames came within 100 yards of their homes.
The Hereford and Worcester fire service was forced first to ask brigades in Gloucestershire, Warwickshire and Gwent for help and then call for 25 Royal Engineers from the Long Marston camp in Warwickshire.
The blaze was believed to have been started by a walker discarding a cigarette in scrubland. The walker tried to put out the fire herself but then called the emergency services and fled the area as the flames took hold.
Firefighters were drawing water from a local reservoir and Severn Trent Water appealed to local consumers to limit use to help ensure supplies to the fire were kept flowing.
West Mercia police sealed off all roads in the area but tonight criticised microlite pilots who were flying over the blaze to view the scene.
"They are endangering themselves and potentially other people as well," a police spokesman said.
Firefighters were expected to remain on the hills for a further 24-hours damping down and dealing with sporadic outbreaks.
The unusually warm winter, spring and summer weather has also ensured a massive increase in the flea and wasp populations. Vets in Britain and Ireland are warning that the flea population was on the verge of exploding.
"There's been a mild winter and they've been living nicely in our carpets," said Karen Bessant, spokeswoman for the British Small Animals Veterinary Association.
"Normally they would have been wiped out over the winter so they were given a nice head start for the summer," she said.
Anywhere used by domestic animals is probably infested with fleas. Once a de-flead animal steps outside it is likely to be pounced upon by hungry fleas.
Wasps are also mounting a summer offensive. Ian Burgess, deputy director of the Medical Entomology Centre at Cambridge University, said wasps had survived well during the early part of the year and were short of food.
Mr Burgess advised: "Always wash the hands after handling sweet foods and wash children's faces.".
When eating outside it was important always to check for wasps before putting food into the mouth. Nearly all wasp-related deaths were caused by stings to the back of the mouth, said Mr Burgess.
The explosion in the insect population has also spurred on a Glasgow- based holiday company to issue midge repellent to customers travelling to the Western Isles.
Douglas Hart, marketing director of Scotsell, said: "We don't want our clients to suffer annoyance, or in some cases pain, when they come under attack. So it's a good investment if people on car tours of the Hebrides can feel safe in the early evening particularly at places close to trees."Reuse content