As safe as the Banks of England

I had heard that the origin of the phrase "safe as the Banks of England" referred to the legendary goalkeeper Gordon Banks, (who was, by the way, phenomenal). Can anyone confirm this?

The original phrase was 'safe as the Bank of England' The pleural 'Banks' could have something to do with Gordon banks but, as a life long soccer fan, who was around in Gorond's hey-day, I've never heard the 'banks' version. It seems to me that it could be a false folk memory.