
Originally Posted by
Magister Militum Flavius Aetius
The Roman Government in Londinium maintained control over Wales, Cornwall, and the area around the Thames until about 440, after which they only had control of the region south of the Thames. It was never sacked, not for decades at least.
These actually existed, but not in the way you imply. A ghost soldier was one listed on the payroll but didn't actually exist so the officers could embezzel money. It was a notorius problem in the Eastern Roman Empire in the 460's and 470's, so bad the Emperor had to past the Edict of Perge (A remarkable set of finds by the way) to deal with it.
It wasn't a problem under strong military leaders like Constantius III or Aetius though.