The Big Question: Why are there two codes of rugby, and are they coming together?

Why are we asking the question now?

Because the former Great Britain rugby league captain, Andy Farrell, is making his England rugby union debut against Scotland tomorrow afternoon. He isn't the first to make the switch - his former Wigan team-mate, Jason Robinson, will be outside him on England's left wing - but such was Farrell's standing in league that his progress in union, where he is winning his first cap after just 11 senior games, is a source of particular fascination to the followers of both sports. England appear to be desperate for the skills they believe Farrell can provide, whilst rugby league fans are curious to see how he can adapt to a completely different role in a different sport.

How long have there been two forms of rugby and why?

For 111 years. There was just one sort of rugby until 1895, when leading northern clubs held a meeting at the George Hotel in Huddersfield and decided to break away, because of the southern-based rugby union hierarchy's refusal to let them compensate players for wages lost whilst playing the game. This issue of "broken-time payments" penalised clubs which relied on working-class players, rather than those who could choose their own hours.

The 22 clubs organised their own competitions, under the banner of the Northern Rugby Union until they adopted the name of Rugby League in 1922. Within three years, they had adopted open professionalism, although on the strict condition that players had to have other, "proper" jobs. Once that happened, clubs had to take enough money through the turnstiles to cover players' wages, so the game had to appeal to a paying public, which it attempted to do by evolving a set of rules encouraging a more open and fluid style of play.

So what's the difference between the two?

It might be simpler to list the similarities, which are that the goalposts are the same and you (usually) have to pass the ball backwards. Among the first things the new game got rid of were two players, reducing teams from 15 to 13, and the line-outs. Other features of rugby union phased out were rucks and mauls and, to a large extent, scrums. In their place, the game needed a way of restarting play after a tackle and achieved that through the play-the-ball, where the tackled player heels the ball back to a team-mate. That is the dominant feature of rugby league and everything else revolves around it. The other big difference was that for 100 years rugby league was openly professional and union was nominally amateur. It was thus a case of "never the twain" where switching from union to league was a one-way ticket, because the professional taint was considered to be for life.

All that has changed in the 21st century, with rugby union going professional in 1995 and no longer having any barrier to bringing back old heroes, like Jonathan Davies, or enticing born-and-bred league men like Robinson and Lestyn Harris. The other big change has been that union, through bringing in league coaches or league admirers like the current England coach, Brian Ashton, has adopted much of league's custom and techniques. On the other hand, critics of the way league is played now argue that the use of the kick is almost as predictable as it once was in union.

Wasn't league supposed to die out when union went professional?

That popular theory underestimated the depth of league's roots. Gates for Super League games in the heartlands been going up for the last few years and there are now amateur clubs all over the British Isles.

Internationally, it has a presence in all manner of unexpected places, such asLebanon and Serbia, and it remains the leading winter code on the east coast of Australia. It is also strong in New Zealand. That being said, it is still a smaller game than union in world-wide terms and, in Britain, one with less financial clout. All the same, the flow of players from league to union has been a trickle rather than a flood and there is still a trickle in the opposite direction.

Is rugby league still flat caps and whippets, doomed to be purely a working-class sport?

It unashamedly has its roots in the industrial north and there is a noticeable difference between a rugby league crowd and a rugby union one. Both have a cliched view of each other as either oiks or Hooray Henrys. The snobbery about league is less marked and the demarcation line less distinct, however, because people from all walks of life decide that they prefer one code to the other. Part of the reason is the rise of the student game which means that movers and shakers all over the country experienced league at university or college. There would be as many degrees in the South Stand at Headingley when Leeds Rhinos play league as when the Tykes play union.

So why is Andy Farrell playing for England tomorrow?

He's a special case. He had done everything in league - apart from beating Australia in a series, which he concluded he was probably never going to do - and was desperate to do something different with what remained of his playing career. The general feeling was that he did not have a lot of rugby league left in him after the punishment he had taken over the last few seasons, and Wigan did not exactly stand in his way.

Will rugby league fans follow his debut?

Even those who dislike the game might make an exception for this one. For one thing, there is the natural curiosity over how a player who ended his rugby league career as a bruised and battered prop translates into a centre in rugby union - it makes you smug when your crocks are someone else's stars. There is also pride in how quickly Farrell made an impact, once he was fit enough to play. It feeds conveniently into the effortless sense of northern superiority that is a birthright north of the Mersey.

Does the cross-over hasten a merger between the two codes' rules?

That was another theory from the time of union's great leap which has turned out to be woefully wide of the mark.

The two games have evolved so far away from each other in 111 years that they do different things for different people. There are similarities, of course, and plenty of people enjoy both, but they are far enough apart that it is possible to love one and hate the other. Any hybrid set of rules would be likely to leave both sets of followers unsatisfied.

One thing that is mildly surprising is that Sky, whose cash finances both club competitions, has not pushed for an annual showdown between the two champions, played under compromise rules. The evidence is, however, that it would be a dog's breakfast - and why bother anyway, when both sports, in their different ways, continue to thrive?