The roots of this episode are in 1895 when the sport of rugby split in two and rugby league was born alongside its often distant relative! We're talking about the codebreakers, those who've crossed over and competed on both sides of the divide.

Outside of our 40-year rule, but who must be mentioned, are Sir Billy Boston, Gus Risman and Clive Sullivan, three players immortalised as 'The Codebreakers' in a bronze statue in Cardiff Bay. All of them rugby league legends who started out playing union in the Welsh capital.

Fellow countrymen who do make the list include Jonathan Davies. A World Club Challenge winner with Widnes and named Man of Steel at Warrington, who many feel his best years as a rugby player were in league. While Iestyn Harris made a big-money move from Leeds to Cardiff, before returning to Bradford where a Grand Final and World Club Challenge followed.

Six Championships, four Challenge Cups and 45 caps for Great Britain and England earned Andy Farrell, at the age of 29, the switch to union with Saracens in a million-pound deal jointly funded by the RFU. Injury curtailed his playing career, but in turning to coaching he led Ireland to Six Nations success and the British & Irish Lions to victory down under.

From that side of the world are contenders in the shape of Wendell Sailor, who not only played both codes, but also appeared on the Australian version of 'The Masked Singer'! Israel Folau, a somewhat controversial figure, actually competed professionally in three sports, union, league and Australian rules football. The late, great 'Inga The Winger', Vai'aiga Tuigamala, capped by the All Blacks and a multiple trophy winner with Wigan. While the 'offload king', Sonny Bill Williams, won the World Cup with the All Blacks in 2011 and 2015 and in-between returned to the NRL with Sydney Roosters winning a Premiership title.

While nearer to home, huge names in the world of rugby in the form of 'Slammin' Sam Burgess, 'Ash the Splash' Chris Ashton and 'Billy Whizz', World Cup winner Jason Robinson, complete our top 10 contenders.