sentences:  The Macclesfield Canal had been authorised by an Act of Parliament obtained on 11 April 1826, but the Trent and Mersey Canal had managed to get a clause inserted into the Act that required them to build the final mile (1.6 km) of the route.It also enabled them to charge tolls for use of the final section, and to receive all surplus water from the Macclesfield Canal.Work began on construction in 1827, and on 20 March 1829 the engineer Thomas Telford wrote to the Trent and Mersey Company, following an inspection he had made of Knypersley Reservoir, Harecastle Tunnel and the Hall Green Branch.