[1] His father, Sir Hector MacLennan, was a renowned gynaecologist and obstetrician.

[1] His mother, Isabel Margaret (née Adam), was a physician and public health activist.

[1] He was called to the bar in 1962 at Gray's Inn and before entering parliament practised as an international lawyer based in London.

Following his stint as SDP Leader in 1988, he served as a front bench spokesman for the Liberal Democrats, and as their president from 1994 until 1998.

[2] Maclennan died at his home in the City of Westminster on 18 January 2020, at age 83.