Never mess with a scaffolder. That is a lesson I learned a long time ago, working as a scaffolder's labourer one summer.

Scaffolding knackers your arms as you lift wooden boards on high, turn the spanners to tighten bolts, and pass incredibly heavy scaffold tubes up buildings. Your arms feel like dropping off. John Shaw, West of Scotland's open side wing forward, was a scaffolder. He is now a blonde.

''It wasn't conducive to rugby in that when I trained and played I was so tired after the heavy job in the day.'' says Shaw. ''But I think a few rugby players would benefit from a job like scaffolding. It certainly gives you arm strength.''

He is a full-time professional rugby player now, but like all of the others in the land, he will only find out if he still has a job when the Glasgow/Caledonia coaches pick their squads, which will probably be this week.

Take a look at the 28-year-old, and what you see is interesting. Having played four seasons for Waysiders, when they marched from division seven to four, his club were on the verge of merging with Drumpellier when a game against West of Scotland changed things.

''Matt Duncan was watching the game,'' says Shaw. ''Evidently he liked what he saw, and the next thing I was getting a phone call from Dougie Livingston to invite me down to training at West. Looking back, it's been the best move I could make.''

Shaw went on to play for Glasgow. But take an even closer look. Two things strike me about Shaw. The first, obviously, is the blond hair. But secondly, he has put on a massive amount of weight.

The hair first. ''Well, some people think it's because I wanted to attract attention, which is wrong.'' he says. ''My wife and I were on holiday in Aviemore and I just wanted a change, that's all. Purely for personal reasons.''

Next, the weight, and here we get an insight, perhaps, into how Scottish players are catching up on others, or maybe it tells us just how much of a head start the likes of the English, South Africans and New Zealanders have had over us.

''I was 14 stone, but now I am 15stone 1lb,'' he says. ''I sat down and I looked at where I wanted to be, and much of the work I needed to do was in the gym.

''I do very specific exercises which I think tie in with my position. I have used Creatin, which you obviously can't use all the time, and I think I am one of the players to have benefited from it. Others don't.

''Maybe I was lucky in that I had quite a bit of experience in the gym before I went full time as a rugby player, but I made up my mind very early on that I wasn't just going to the gym to muck around. It was work.''

Shaw has changed his shape, and his strength, and I have to say that, whereas he was just one of the numbers in previous years, this season he has been a stand out. High work-rate, strong arms, a willingness to go on the wrong side of the ball, and a bit of pace and decent hands, are all his.

In a West of Scotland team full of name players, it has been Shaw, for my money, who has made that little bit of difference in each of their games.

''Yes, it's been a good season for me and the club. There is a positive attitude which has been pleasing, and yet we all know we could have played much better in many matches,'' says Shaw.

''Now we are in with a chance of winning the championship, and I think if we beat Watsonians we'll do it. The key to it has been the senior players.

''Brian Edwards and Muff Scobbie have created their impact, but there are a lot of us who are playing and training as full time professionals and we know that when we go to training it is a job of work. The team get on well together and we like winning.''

One of my lasting memories of Shaw was when Glasgow played Montferrand, and got blown off the pitch in the process, in last year's European Conference.

He looked too small for the fray, but got stuck in nevertheless when others were posted missing. Maybe professionalism has come too late, but you are only as old as the woman you feel and there's a role model in Shaw for some of the younger players. ''My ambition is still to get some sort of thistle on my chest,'' he says, by way of parting.

Maybe he will. He has to get another SRU contract first and, being a scaffolder, he could easily twist a few arms to help him.