Mountbatten was a British individual involved in the Partition of India.
When Prem accused the British of "carving [his country] up slapdash in six weeks," the Thirteenth Doctor noted she would pass his thoughts on to Mountbatten. (TV: Demons of the Punjab)
Behind the scenes
In real life, Louis Mountbatten, 1st Earl Mountbatten of Burma, was the last Viceroy of British India and the first Governor-General of independent India, heavily involved in the partition.