Jonathan Davies: Farrell could hold the key to England's World Cup - just ask Jason Robinson

Andy would probably find it more natural to play at No 1

If Jason Robinson hadn't moved from rugby league to union I don't think England would have won the World Cup. They were a great team, but he still managed to make the difference when it mattered. Those who are queueing up to berate the decision to move Andy Farrell from league to union should remember Jason's contribution.

You can't compare them as players, but I believe Andy can still make an impact on next year's World Cup. He could be the one to make the difference. It hasn't helped his cause that Saracens and England spent most of last week arguing about what his best position is. It's astonishing that he's been in the game 18 months and they are still at loggerheads about where he can be best used.

That's the trouble with trying to serve two masters, but one thing is certain: far from being an "act of desperation", as Jeff Probyn calls it, acquiring Farrell was a very inviting investment at the time. He was the best-equipped player in either code and England were not exactly bulging with talent. They aren't now, come to that.

His outrageous bad luck with injury, plus being in a car crash, means he is only just beginning to make the difficult transition. When he starts playing regularly, it should become clearer where he'll be most valuable, but it would have been much easier if they had plotted a course for him to follow.

When I went from union to Widnes in 1989, their coach, Doug Laughton, knew exactly what role he wanted me to play. They were a great side with no weaknesses but he told me I was the final piece in his jigsaw. It was still difficult to get used to the new game, but at least I knew where I was going. As a winger, Robinson occupies the most straightforward position to make a successful changeover, but it still took him a long while before we saw him at his brilliant best.

Chev Walker has recently crossed over from league to play for Bath and I reckon he'll be an asset, because he can be precisely what they want, and that's a big, strong lump who can carry ball over the gain line. He's not going to give them a kicking game or produce the skills of a creative union centre, but he will provide what they need.

Taking players from one code to another is all about cherry-picking, selecting the abilities you need. In Farrell's case this was more difficult, because he has so many excellent abilities to choose from and England had so many areas in which they needed strengthening.

When I saw that he was going to be played in the back row on his debut the other week, I felt it suited the way he runs with the ball and makes the big hits. And, let's be honest, there's not a mass of good back-rowers banging on England's door at the moment.

I wasn't sure about blindside. He'd get a lot more ball at No 8 and would be able to dictate more. Now that time is running out, he would probably find it more natural to play at No 12, where there is a glaring gap to fill after Will Greenwood. At inside-centre Farrell would be able to use his terrific kicking game and apply the full range of his skills in loose-phase play.

I don't accept the inference that league players can't hack it in union. But certainly for forwards it is a tougher assignment.

The RFU said last week that they were going to become more selective in investing in league players in the future. Does that mean they haven't been selective in the past? If not, it's a strange admission.

At least they can't question the motivation of league players who cross the line. In my day, there was only one incentive, and that was money. It was the only way we could make a career out of our rugby skills.

When players of Farrell's ability make the change, they aren't looking for money. They are well- paid in league. What drives them is a genuine interest in the challenge of adapting to a new game and playing for their country at a level that carries a much higher profile than in league.

Not all the modern converts will succeed but they should be credited with the courage to attempt to take their careers to a new height. Knowing Andy Farrell, he'll be all the more determined to do just that.