Fires hit Northern Ireland, north-west England, and several areas of Scotland including the Balmoral estate, as well as Swinley Forest in Berkshire
Heathland fires have been burning across parts of the UK for days amid unprecedented dry weather, with no respite on the horizon until the weekend.
The hottest April on record, which registered only 21% of expected rainfall in England and Wales, has hampered the efforts of firefighters and caused vast areas of parched land to go up in flames.
Blazes fanned by high winds have been seen in areas of Scotland, England and Northern Ireland, with hundreds of firefighters called in and helicopters used to drop water in the worst-affected regions.
The weather forecast shows little chance of any substantial rain falling before Thursday, with central and eastern England having to wait until the weekend. Roads have been closed and 170 firefighters have been called to the Swinley Forest area of Berkshire, where a number of fires broke out. In the north-west of England in Lancashire, fires began on moorland in Belmont, near Bolton, as well as in Ormskirk and Bacup.
Police in Northern Ireland are investigating reports of a man seen with a petrol can close to one of the worst gorse fires for years in the Mourne mountains. There were reports of two youths lighting fires in south Armagh. Hundreds of acres of land are being destroyed and homes and livestock threatened by fires which burned for much of the bank holiday weekend in counties Down, Armagh and Tyrone.
Scotland, where the royal estate of Balmoral is affected among several other areas, and Northern Ireland had just two-thirds of the rain normally expected in April. The average temperature in England was the hottest since records began 353 years ago.
Despite the dry weather, the Environment Agency is not planning a hosepipe ban. A spokesman said: "We feel confident there is enough water to see out spring and summer without restrictions on the public supply."