Peak UK track mileage for trams?

[WightMark]

Has anyone ever worked out what the peak track milage was for all tram lines built in the UK? (Notice peak rail is approx 33,000km around 1907...ish). Just wondering how many other lines we could add to that to figure out the maximum amount of steel-rail that once covered our little islands?!

EDIT: I refer the honourable members to some great maps like this which show the spread of trams in our conurbations

 

[Dr Hoo]

Could you clarify if you mean track mileage or route mileage? (The ‘heavy rail’, err, kilometrage seems to suggest routes.)

Having had time to check my library, in the common text, Tramway Heyday, J Joyce quotes ‘peak tram’ as being in the mid-1920s, with 2,600 miles of route, 14,500 vehicles and 4,700,000,000 passengers.