A 27-year-old woman has been arrested on suspicion of child neglect after a house fire in south London caused the death of two pairs of twin boys, who had been left alone at the property. The boys, aged three and four, were given CPR by firefighters at the scene in Sutton. They were taken to hospital, where they died. The cause of the blaze on Thursday evening is being investigated by fire teams and the Metropolitan police. Chief Supt Dave Stringer, borough commander for Croydon, Bromley and Sutton police, confirmed that the children were related. He said: “There was nobody else inside the property at the time of the fire.” The woman arrested on Thursday night remains in police custody, he said. Stringer said: “London fire brigade colleagues acted heroically in recovering the children and I want to pay particular tribute to them. I know this incident would have a lasting impact on them and other police officers and paramedics who are involved. We will make sure they get the support they need.” Mourners laid floral tributes, candles and teddy bears outside the police cordon throughout the day on Friday, with a message on one bouquet reading: “To Kyson Bryson Leyton + Logan. Sleep well. Love Grandad.” Eight fire engines and about 60 firefighters were sent to Collingwood Road in Sutton shortly before 7pm in response to reports of a fire. The first firefighters arrived three minutes after being called and faced an “intense blaze” throughout the ground floor of the mid-terrace house, they said. The blaze was under control by 8.36pm. The London fire brigade deputy commissioner, Richard Mills, said that after attempting to resuscitate the children on the street, some of the firefighters had followed the ambulance to hospital to make sure resuscitation efforts were not interrupted. Some of the firefighters, he added, have needed counselling as a result of the tragedy. “Entering a building and rescuing life is always a very difficult place to be,” he said. “The age of the children, the fact they are so young, will have a profound impact on them [the firefighters].” The roads around the scene of the tragedy remained closed as people laid floral tributes, candles and teddy bears for the four children. A local woman, who did not want to give her name, said the four boys often came to her shop with their mother. “They were always all holding hands, they were so well behaved, so polite,” she said. Another person who lived nearby said: “It’s absolutely devastating. Those children have passed my house many times and they were always very happy, very polite young boys. She was a good mum. How did this happen?” The Rev Frances Arnold at nearby St Nicholas church said: “It’s a great shock and tragic loss of life, young children, and so we’ll continue to offer our prayers for the family, the friends, the community here, the emergency services.” Matt Gray, the manager of Sutton United football club, laid yellow-and-black team scarves outside the police cordon at the scene. He said it was “such a tragic event to happen on our doorstep” and “a huge shock and obviously very devastating”. Two of the boys were pupils at Westbourne primary school in Sutton. In a statement, the school said: “Westbourne Primary School and its entire community are devastated at the news of the tragic loss of the four children; our hearts, thoughts and prayers are with the family and anyone else affected by this heartbreaking event. We will continue to support the children, the staff, the families and the community through these very difficult times.” The home secretary, Priti Patel, tweeted: “My thoughts and prayers are with the families and loved ones of the four young children who tragically lost their lives in the fire in Sutton yesterday. I am being kept updated by the emergency services and I would like to thank them for their work in such sad circumstances.”