Fire crews are on alert as the driest start to summer for decades puts moorland at risk of devastating blazes.

Already there have been two fires on Ilkley Moor, blamed on arsonists, this week, and countryside officers are on stand-by with firefighting equipment as temperatures continue to rise.

West Yorkshire Fire Service has also issued a warning to visitors and homeowners to be extra vigilant as land becomes tinder-dry.

A 100-metre strip of land near the 12 Apostles was scorched on Sunday evening, and land near the Cow and Calf Rocks set alight on Tuesday night.

Gamekeepers rushed to the scene to dampen out the flames.

Bradford Council countryside officer Richard Perham said he was concerned about the risk of further fires, and urged everyone not to discard cigarettes or glass bottles which could potentially spark a blaze in bright sunlight. Barbecues were also a risk, he added.

“The fires are usually deliberate,” he said. “The most common cause is a discarded cigarette or starting them deliberately with matches or a lighter.

“In the past we have put up fire notices, but sometimes we think that’s an incentive rather than a prevention. There’s no doubt it’s very dry. We will just have to watch out and try to get there as fast as we can.”

Latest statistics issued by the Centre for Ecology and Hydrology show rainfall across the UK between January and May has been the lowest since 1964, with Yorkshire receiving just a third of its average rainfall for May.

West Yorkshire Fire Service has warned people to be careful in the dry conditions, even in their own gardens.

A spokesman said: “Although we think being outside is safe, there are quite often things in gardens or on the moorlands which catch fire. We would urge people to take care and not to discard things.”

Bradford Council Countryside Service has been working with the South Pennines Fire Operations Group – a partnership of landowners and rescue services which was set up in the wake of the week-long fire which devastated Ilkley Moor in 2006. Teams are now equipped with fire-fighting tools such as a 1,000-litre water tank and power hoses.

The Met Office is forecasting continuing dry weather with sunny spells for this weekend, with temperatures up to 24c.