Caledonian Canal Act 1840 was passed on 4 August of the same year, "to authorize the Commissioner's of Her Majesty's Treasury" to allow for the leasing and management of the canal.
The Caledonian Canal from Moray Firth to Loch Linnhe was completed on 30 October 1822 and opened the same year. An Act of Parliament establishing the Caledenian Canal Commissioners was passed on 27 July 1803, and the commissioners made a corporate body in 1848. Both this canal and the Crinan Canal were subsequently privately leased in 1860.
References
Caledonian Canal Act 1840 Wikipedia(Text) CC BY-SA