 The swim took him 21 days to complete.The official headwater of the river had stopped flowing due to the drought forcing Pugh to run the first .Since June 2012 the Port of London Authority has made and enforces a by-law that bans swimming between Putney Bridge and Crossness, Thamesmead (thus including all of central London) without obtaining prior permission, on the grounds that swimmers in that area of the river endanger not only themselves, due to the strong current of the river, but also other river users.