Alastair John Morrison 3rd Baron Margadale DL (born 4 April 1958) is a British peer.Margadale is the son of James Morrison 2nd Baron Margadale and Clare Barclay. He married firstly Lady Sophia Cavendish daughter of Andrew Cavendish 11th Duke of Devonshire and The Honourable Deborah Mitford on 19 July 1988.