CLERKENWELL STATION

Kings Cross and Farringdon stations look close together on the tube map, but they are approximately 1.8km apart, or a little over a mile. As far as I am aware, this is the longest distance between Underground stations in Central London on the same line. By comparison, Leicester Square and Covent Garden are only 260m apart, a little more than the length of two Piccadilly Line trains.

The intersection of Roseberry Avenue and Farringdon Road falls just south of the midpoint between Kings Cross and Farringdon. It is already served by four bus routes, and would therefore make a good location for an Underground station, which I shall call Clerkenwell. In addition to residents and businesses in the area, the new station would serve Exmouth Market and the Mount Pleasant sorting office. This map shows the location of my proposed station.

Unfortunately, building a station in this location would be very challenging, which is probably why it has never been done. Whereas most of the Circle line runs in cut-and-cover tunnels just below the surface, at this point the line is in a deep tunnel known as Clerkenwell tunnel. What's more, the Thameslink lines run in a parallel tunnel, and somewhere nearby is a culvert carrying the Fleet River.

The point, just north of Farringdon station, where the Circle, Metropolitan and Hammersmith & City lines cross over the Thameslink tracks. Just beyond this point, both railways enter tunnels.