We asked DfE whether the 64,000 buildings on the school estate include temporary buildings, Portakabins and similar blocks. It replied that the first Condition Data Collection programme (CDC1), from which the total number of buildings was derived, did include such buildings. DfE later clarified that the CDC1 visits, which took place from 2017 to 2019, had identified 5,749 relocatable mobile blocks in use across the school estate. DfE also explained that many school rebuilding projects—especially for secondary schools—involve rationalising several old blocks, some of which are temporary, into a single new block.43