He served from 1947 to 1948 as chairman of the tribunal set up to arbitrate between Indian judges disagreeing over the concept and substance of the Partition of India which had been announced by Lord Mountbatten and was being detailed by Sir Cyril Radcliffe's two boundary commissions (one for Bengal, one for present-day Pakistan).

[5][6] Spens returned to Britain in 1949, and the following year he was elected as Member of Parliament (MP) for Kensington South.

After his retirement from the House of Commons in 1959 he was raised to the peerage as Baron Spens, of Blairsanquhar in the County of Fife.

Spens married firstly Hilda Mary, daughter of Wentworth Grenville Bowyer, in 1913.

After his first wife's death in 1962 he married secondly Kathleen Annie Fedden, daughter of Roger Dodds.