He has refereed no fewer than six 147s: two by John Higgins and one apiece from Jason Prince, Barry Pinches and Nick Dyson. Remarkably, on four of those occasions the player who made the maximum lost the match.
Williamson has also officiated semi-finals of the British Open and Welsh Open.

His hobbies away from the table include supporting Liverpool FC, photography, visiting the theatre and watching live music including U2, Bon Jovi and Jules Holland.

Date of birth: July 26, 1948

Born: Broadgreen, Liverpool

Lives: Broadgreen, Liverpool

Highest break: 57 clearance

Qualified as a referee? In the late 70’s but qualified for the professional game in the early 1990’s.

First Pro match? It was at Bolton, probably 1991, and Simon Westcott was one of the players involved.

Most memorable match? I’ve been lucky to officiate six 147’s. But I remember a match between John Higgins and Anthony Davies in the Welsh Open. John won 5-3 in about 90 minutes. There were about four centuries and a 90. I wore a new pair of dress shoes and ended up with four blisters!

Most embarrassing moment? Doing four frames at the UK Championship one year with my fly open!

If you weren’t a referee what would you do? I spent 23 years working at Liverpool Airport so I suppose I’d be doing something in aviation.

Which is the toughest rule to apply? It has to be the miss rule though it has become a lot easier now than when it was first introduced. Players and referees now know what is expected of them. The interpretations weren’t always as clear cut.

Which rule would you scrap? Probably the simultaneous hit. If players think there is a chance of being called they strike the balls at 100 mph. You need slow motion to spot it.

What do you carry in your pocket? Two ball markers, a pen and a £5 coin.

Where do you get your gloves? Surprise, surprise….Paul Collier.

Interests? Photography, dining out, going to rock concerts.