Williamson was largely responsible for co-ordinating the huge rebuilding project at St Cuthbert's by architect Hippolyte Blanc in 1892-4. This was partially funded by his predecessor Rev James Veitch. As a somewhat immodest part of the rebuilding he included a plaque to himself on the outer west face and to Rev James MacGregor the first charge minister balancing his memorial on the opposite side of the tower.Fasti Ecclesiastae Scoticana by Hew Scott
