In 1935, he was selected for Hendon Police College, passing out with the Baton of Honour the following year.
During the Second World War, he served as public safety officer attached to the 8th Army in Italy.
In 1952, Webb was promoted Chief Superintendent commanding Bow Street division.
In 1953 he transferred to West End Central and in 1954 he was promoted Deputy Commander at Scotland Yard.
In 1961 he was appointed Commander of the Royal Victorian Order (CVO) and Officier of the Légion d'honneur.