Gas meter on Upland Road/Lordship Lane corner

[Lowlander]

Block of flats on the corner of Lordship Lane/Upland Road have four gas meters on the outside.

The one furthest from Lordship Lane is in a constant state of flux - the housing is off for a few days, then it's back on; the parts are always in a different position and it looks like it's hanging off the wall.

It's not a prepaid meter so no constant access, and the other three meters are untouched.

Can anyone reveal the story? It's been like that for years, but only just got to me!