McIntosh was born in
Kildrummy near
Nairn in 1768, apparently attending
Inverness Grammar School before working as a
navvy on the
Forth and Clyde Canal and later the
Lancaster Canal, where he first worked as a contractor. While working on the Lancaster Canal, McIntosh met fellow Scot
John Rennie who helped nurture McIntosh's career. McIntosh followed Rennie to London to work on the city's docks, and his growing reputation as an engineer led to him being recruited by the British government in 1809 in an ultimately unsuccessful attempt to demolish fortifications at
Flushing. and, in 1815, to work on the
Surrey Commercial Docks. With a reputation for honesty and a business with sufficient resources to complete major projects, he became the leading contractor of his day, undertaking contracts including work on the
British Museum,
Hampton Court,
Brighton Pavilion,
Buckingham Palace (working for
John Nash), the
Aire and Calder Navigation and
Goole docks, dock works at
Portsmouth and
Southampton, the
Mythe Bridge, and the
London and Greenwich Railway. In 1837, ''
The Gentleman's Magazine'' celebrated the railway project saying: :"This great national work reflects the highest honour on the gallant proprietor,
Colonel Landmann, no less credit on the contractor, Mr Macintosh, under whose orders no less than 60,000,000 bricks have been laid by human hands since the Royal assent was given to the Act of Parliament for its formation in 1833." ==Family life==