He was born on 14 December 1820 the son of Jane Whiteside and her husband, the eminent Edinburgh physician
David Maclagan. His childhood home was 22 George Street in the centre of
Edinburgh's New Town. He was educated at the
High School in Edinburgh and the
University of Edinburgh but did not graduate. He then went to
Addiscombe Military Seminary near London. He joined the Honourable
East India Company as a 2nd Lieutenant in 1839. He then went to the School of Military Engineering in Chatham, to specialise as an engineer. He arrived in Delhi in India in 1842. He was in charge of the engineering works for the defence of Lahore in March 1846. Following severe illness he was given more sedate duties, including running the Civil Engineering College at
Rurki aged 27. In the Mutiny of 1857 he successfully defended Rurki against the rebel forces. In his military career he rose to the rank of General, first in the Bengal Engineers then in the
Royal Engineers. In 1853 he was elected a
Fellow of the Royal Society of Edinburgh his proposer being Sir
Robert Christison. From 1861 he ran the Public Works Department for all of the
Punjab.
Queen Victoria created him a Knight Commander of the
Order of St Michael and St George (KCMG) for his efforts. He retired in 1879. He spent most of his final years between Edinburgh and London. He died in 1894. ==Family==