By 1890 it was clear that despite the Queen's reluctance to lose him from Windsor, Davidson's promotion to a bishopric was overdue. He was offered the choice between two vacant dioceses: Worcester and Rochester. At the time – before the creation of the diocese of Southwark – Rochester included all London south of the River Thames, and was the third-largest in England. Davidson chose it in preference to Worcester, explaining to the Prime Minister, Lord Salisbury, that from his years at Lambeth he knew the area and its clergy so well that he was certain he could do more there than in Worcester, which he hardly knew.