More than 10 per cent of trusts and councils still haven鈥檛 responded to a vital government survey on 鈥渃rumbly鈥 reinforced autoclaved aerated concrete (RAAC). Officials have been asking responsible bodies to complete questionnaires on the presence of the potentially dangerous material on their sites since last March. But speaking in the House of Lords on Tuesday, academies minister Baroness Barran said: 鈥淣early 90 per cent of schools and responsible bodies have sent in their initial responses [to our questionnaire] and we are working closely with structural engineering sector to identify accurately both if the RAAC is present and if it poses a risk. 鈥淲e鈥檙e now running a small call centre within the department and there are, including sadly some local authorities, organisations we鈥檝e had to contact multiple times. We鈥檙e working with MPs and others to make sure we get all the returns.鈥 Barran added that she is 鈥渧ery confident we will have carried out at least 600 surveys by the autumn鈥. This comes amid fears from the Office for Government Property that the 鈥渃rumbly鈥 material, used widely in flat-roofed school buildings, is 鈥渓iable to collapse鈥. Last week, seven schools 鈥 spread across Kent, the north east and Essex 鈥 were temporarily closed following discovery of RAAC on their sites. 聽 According to a Local Government Association report, seen by Schools Week, more than 150 schools 鈥渉ave been identified as potentially having RAAC鈥. Last March, the Department for Education asked responsible bodies 鈥 trusts and councils 鈥 to Barran described this as a 鈥渟uperhuman task鈥, and although a 鈥渧ast majority鈥 had responded, 鈥渁 handful鈥 had not. Speaking to Schools Week she said: 鈥淚 find that really baffling, because we are here to help them. We鈥檝e lined up a lot of capacity in terms of structural surveys and so forth.”