This is the moment firefighters battle to stop a large field blaze from ripping into homes, as fire chiefs warn the weeks of hot, dry conditions have turned Britain into a tinderbox.Flames leapt through three fields in Cambridgeshire over the weekend, as the country braced for soaring 35C temperatures this week amid the fourth heatwave of the year.Footage shows the fire spreading through a large arable field near the village of Peakirk, leaving swathes of scorched earth behind.Thick smoke can be seen forming large plumes in the sky and blowing among a nearby village.Some 35 firefighters were needed to tackle the blaze, with Peterborough Volunteer Fire Brigade first on the scene at around 3.30pm on Saturday.There were fears the flames would blow over to houses and allotments across the fields.Anthony Gould, the brigade's chief officer, said: 'We were kind of in the thick of it, it was hard work for everyone involved.'Cambridgeshire Fire and Rescue Service, which supplied the bulk of the response, said it was called out to 20 fires within a few hours over the weekend. Thick plumes of smoke formed over burning fields near Peakirk, Cambridgeshire Firefighters doused the burning vegetation with their hoses, stopping it from blowing towards houses The UK is currently in the grips of a fourth heatwave of the year, with temperatures approaching 30C on TuesdayTemperatures are expected to peak on Wednesday and could tip the mercury as high as 35C in parts of the southeastAround 50 of its crew attended another field fire on Sunday in Whittlesey – with Group Commander James Ball warning farmland blazes were one of the biggest risks during the hot weather. Officials are already on edge after watching the devastating fires spread through France and Spain – and fire chiefs have warned there is a risk of wildfires over here as well.A National Fire Chiefs Council (NFCC) spokesperson said: 'Fire and rescue services have already faced significant pressure this summer, responding to wildfire incidents during prolonged spells of warm and dry conditions.'With the potential for further hot weather ahead, services remain prepared and ready to respond.'They called for Brits to be extra cautious with anything that could start a fire, including disposable barbecues and cigarettes.At the height of the third heatwave in mid-July, firefighters were battling 19 significant wildfires simultaneously in England and Wales.Since then, a major fire has burned for two weeks in the Cairngorms, with nine fire engines and 75 firefighters still at the scene near Nethy Bridge on Monday. Amber health alerts have this week been issued to reflect the danger of the short, sharp burst of heat, alongside warnings for Brits to avoid sitting under trees, in case of falling branches.South-east England will see the most extreme temperatures, peaking on Wednesday when the mercury is expected to climb into the mid-30s.Amber health alerts kick in at 9am on Wednesday for the South East, East, and East Midlands, and are set to last for 24 hours. Grass in Blackheath, south-east London, has turned entirely brown Weeks of minimal rain and the second hottest month on record in the UK has left the fields severely parched A woman sunbathes on the scorched grass in Wimbledon Park over the weekend Grafham Water, a reservoir in Cambridgeshire, has dried up considerably under the heat Scorched fields at Bramcote Hills Park in Nottingham, where a dedicated wildfire unit was set up last week