Q. How close do you allow yourself/yourselves to get to the players? Do you consider each other friends or just work colleagues?
Estesark

Williams watches Stuart Bingham in action at Wembley Arena

A. On the table, no way. Obviously we are impartial and we would never favour one player over the other. People might wonder if I was reffing a Welshman, for example, whether I would favour him, but it would never even cross my mind.

Off the table though, we are friendly with the players because we are all part of one big family. Especially when you're overseas, we all tend to travel together and stay in the same hotels, so you do form friendships. We will have a laugh and a joke and a pint with anybody who will pay!

Q. What would the referee do if the cue ball was completely surrounded by balls other than the object ball and therefore absolutely impossible to play anything other than a foul shot?
poorpotter

A. This is one of those situations where it is, effectively, an automatic foul because no matter what shot he plays he's going to give away a foul. In that situation, you wouldn?t call a miss because otherwise the other fella could put him back in and you'd be there all day.

Basically the player has got to play in a direction as if he was trying to get out of it, and with enough strength that ? if the obstructing balls weren't there ? he would have reached the colour he nominated. He's in a no-win situation and just has to do his best.

Q. How do you decide who refs the final of a major tournament?
jameslfc147

A. The tournament director decides which referee gets the final, and it usually gets decided fairly early on in the season. It's more or less done on a rotational basis within the elite referees.

Obviously you can't let everyone have a final, and there is a pecking order of seniority but it is nice to give the younger refs coming through a bite of the cherry.

A new person to the Crucible normally does rounds one and two. The next year he gets one, two and a quarter-final, then a semi-final and so on.

You build up a trust with the players over the years, and they know that you're not calling fouls for the sake of it

I was over the moon when I got told I was going to do my first final in 2001, there's no feeling like it because it's the top job that we all aspire to do.

I was gobsmacked, and in the same way that people know where they were when they heard JFK was assassinated or Princess Diana had died, I can remember where I was when I got that news. It was at the Newport Centre doing some qualifiers, and I felt 10 feet tall afterwards.

Q. What kind of standard did you reach as a player?
Phil Harlow, BBC Sport journalist

A. I used to play on the amateur circuit, but not really seriously. I was nothing special, to be honest, and I had a top break of 49.

I could give most people a good game, but I never won as much as I would have liked to, so I thought that if I wanted to get on in the game it would be as a referee, not as a player.

Q. I once saw a top ref call a foul only to retract it when the offending player quickly denied it. If a player denies a foul like this will you always give them the benefit of the doubt?
Kriss_boy

A. When you call a foul on a player, you have to be 100% convinced that an offence has been committed, there's no point in being 99% sure.

I've had players question my decisions on numerous questions, but virtually every time they have accepted my ruling because I am the ref. You build up a trust with the players over the years, and they know that you're not calling fouls for the sake of it.

Q. From all the matches you have watched, which would you most liked to have refereed?
wildJONESEYE

A. It's a tricky question, and the obvious answer ? and the one that immediately springs to mind for me ? is the 1985 World final between Dennis Taylor and Steve Davis. That was some match and it was actually refereed by another Williams, John.

This Williams certainly wouldn't have minded a go at that game!

All week during the Masters, top officials will answer your questions.