The batteries were part of the northern defences of Gibraltar. Armies can only attack Gibraltar without ships from the north and therefore this is heavily fortified around the only gate to Spain called Landport. Cornwell describes how this was defended by "several batteries, numerous batteries on the Glacis of Landport, by Crutchett's and the Grand Battery". He speculated that no army could withstand the grapeshot from 400 "pieces of heavy artillery".
