There's at least four different River Banks in the UK. Without more specific information, we'd just be guessing.
3.3 miles
Distance between piccadilly St. Pancras
The St. Pancras station is located in London, England. It is also known as London St. Pancras station. It is owned by London and Continental Railways.
About 40 miles but if you're in London, catch the Eurostar train from St Pancras and it passes through Ebbsfleet.
The London St Pancras railway station is a terminal train station that is renowned for its Victorian architectural design. The railway station is also known by the name London St Pancras.
London St Pancras International Station.
About 3 miles.
St Pancras International.
St Pancras
St. Pancras stationEurostar is the brand name of the company running high speed trains London-Paris and London-Lille-Brussels through the Channel Tunnel.Eurostar uses the stations: St. Pancras (London), Gare du Nord (Paris), Bruxelles Midi (Brussels) and Lille Europe.Currently these are the only passenger trains operating through the tunnel.The Eurostar takes 2 hours 15 minutes between London and Paris.
Well - it's a distance of about 58 miles - so your best bet would be to phone a London taxi firm and ask for an estimate (but it won't be cheap !)
St Pancras.