[3] He was Managing Director of Crookes Laboratories[4] (1962–1972) where he was responsible for securing the license for an early anti-depressant in the UK, Prothiaden.

Following graduation from Cambridge, Ash lectured in mathematics at The Bedford College for women[6] for three years[5] before joining Guinness & Co. as a mathematician at their London Brewery in Park Royal in January 1951.

Speaking at Guinness in March 2016, Ash said: “…We had to decide ourselves that the perfect head was three eighths of an inch…it just looked right.”[3]Nitrogen is less soluble than carbon dioxide, which allows the beer to be put under high pressure without making it fizzy.

The high pressure of dissolved gas is required to enable very small bubbles to be formed by forcing the draught beer through fine holes in a plate in the tap, which causes the characteristic 'surge'.

[3] Ultimately called the "easy serve system,"[7] in late 1959 it began to replace the old "high and low" taps used in Ireland, before spreading to Great Britain and beyond beginning in the 1960s.

"[6]The invention, which made for a smoother, less characterful beer, was not without controversy, and for years a minority of Irish drinkers complained about the change.

From 1970 onwards Ash followed various interests including business education and was a founding governor of Templeton College Oxford.