AP
True to a point... but at FL100 or above it's not called LARS, nor strangely MARS? Probably because LARS was a concept introduced in the 70s when transit services were only available from area radar units, but it was recognised that there was a growing need for a service "down among the weeds"... and as most airfields now had, or were getting radar, they were volunteered.
(PS: London (Mil) is no longer called London (Mil) anymore, since the move to Swanwick... hard to keep up, isn't it?)