In the 1920s, the old mills were demolished, and the bulk of the river flow was diverted around Laundress Green via new sluices from the upper river, instead of flowing straight past from the mill races. This new flow had to turn sharply in the Mill Pool to flow past Queens', with the result that the river began to scour away the foundations of Silver Street bridge and the Essex Building. By 1938, the Essex Building was so undermined that it began to collapse into the river. A major rescue operation involved underpinning the foundations with a concrete shelf below water level, and pulling the building back upright with tie-rods, the plates on the end of which can still be seen. At about the same time in 1938, demolition of Essex Building was being considered to permit the widening of Silver Street.
Sketch designs exist for a replacement building .
The road widening scheme was turned down, and Essex Building survived. The river continued to scour away the foundations of the Silver Street bridge of 1842, which eventually had to be taken down in 1959 to be replaced by the present bridge, to an earlier design by Lutyens. He modelled the balustrade of the bridge on that of the roof of Essex Building.