Richard J. wrote:

By contrast, Metro's fleet of Class 313, admittedly around 13 years
older but maintained in the same Bletchley depot, achieved a miserable
5189 miles per casualty last year, compared to FCC's 11,355 mpc with
the same class.

Intially Bletchley but, more recently, Willesden. Reliability plummeted when
Willesden took over responsibility.