This street changed substantially in the 20th century. The corner from St Mary's Street to St John's street was a very dangerous corner resulting in many accidents.

In 1938 a new A1 inner relief road was proposed across the meadows, through Sheepmarket to link up with Scotgate but the war in 1939 curtailed any such construction. In preparation for this and to improve access, it was decided to widen Castle Street by demolishing the buildings on its the north side.

St. John's Street was also to be widened and as a first stage the London Inn, on the corner was rebuilt fifteen feet further back and the medieval timber-framed buildings at numbers 5,6,7 and 8 St John's Street were demolished.

The new London Inn was designed by Henry Traylen, a local architect responsible for saving many examples of Stamford's history threatened with demolition. See the Stamford Civic Society website for more information.