[1] His father was Jim Williamson, founding proprietor of the Northern Snooker Centre in Leeds.

[3] In 1976, he beat Davis in the semi-final of the Under-19 Snooker championship before losing to him later the same day in the billiards final.

[4] Williamson won the Under-19 billiards title in 1977 and 1978, beating John Barnes in the final both years.

[6] The following year, Williamson lost 7–5 to Bill Oliver in the final of the 1981 Pontins Autumn Open.

[10]: 178  In a 2005 article, former billiards world champion Geet Sethi described Williamson as "justifiably accused as one of the slowest players on the circuit.