 Complete the following phrase:  The regiment was formed on 10 July 1940 as part of the rapid expansion of Britains Anti-Aircraft AA defences during the Battle of Britain. It was originally constituted with 500 to 507 LAA Troops, which had been formed on 1 July. It was then joined by 102 and 135 LAA Batteries, which had been formed on mobilisation of the TA 2325 August 1939 and by 142 LAA Bty transferred from 22nd LAA Rgt, a TA unit based in Birmingham. It formed part of 1st AA Bde, which had been reformed after the 