He was chairman of Crosswells Brewery in Cardiff[4] and director of the Cardiff Docks and Railways company, Rhymney Railway company,[5] the Great Western Railway company, Anglo-Ecuadorian Oilfields and Lobitos Oilfields Ltd, Mount Stuart Drydocks Ltd, and Cardiff Exchange Co Ltd.[2] Tatem was a DL and JP for the county of Glamorgan, of which he became High Sheriff in 1911, as well as becoming a JP for Wiltshire in 1922.

[2] He was created a Baronet in 1916[6] and raised to the peerage as Baron Glanely, of St. Fagans in the County of Glamorgan, on 28 June 1918.

[10] In 1937, he helped the National Joint Committee for Spanish Relief to open a home at Cambria House, Caerleon for 50 Basque child refugees.

[2] His horses won six British Classic Races: Tatem married, on 14 September 1897, Ada Mary, daughter of Thomas Williams of Cardiff, Wales.

The couple had one son, Thomas Shandon Tatem, born 20 July 1898, who died on 14 June 1905 aged six years.

[3][8] Lord Glanely was killed during World War II in an air-raid in Weston-super-Mare in June 1942, aged 74,[14] when, having no surviving heir, his titles became extinct.