Although Croydon is a London borough, it's quite far outside of central London, to the point that it doesn't really feel part of London. It's also quite a deprived area. So that quote is weird on a number of levels!
Scotland isn't included, so I can't compare Strathclyde, but Blackpool's average is 5,900 — and includes 8 of the 10 most deprived places in the country.
Only one bit of London (part of Haringey) makes the top 1000. Only 106 bits of London (out of 4685) make the top 10%.
[1] https://www.gov.uk/government/statistics/english-indices-of-...
"Both Croydon and Strathclyde are shit places, but Croydon is a little less shit. By spending that pound in Croydon we can hopefully avoid it becoming Strathclyde"