Alexander MacCallum Scott (1874-1928) was Liberal MP for Glasgow Bridgeton.
He won the seat in December 1910, held it as a supporter of Lloyd George's coalition in 1918, but lost it in 1922. Two years later he joined the Labour Party. He was earlier president of Glasgow University Union and the first biographer of Winston Churchill (works published 1905 & 1916).
Served on Lewisham Borough Council 1903-6 (Who Was Who 1926-28).
The Wikipedia page is [1]. Details of his archives 9held at the University of Glasgow) here, here and here.