The four home unions have agreed a 24-team British & Irish Cup that will begin next season, it was announced today.
The second-tier competition will feature 12 sides from the English Championship, six from the Welsh Principality Premiership, Irish provinces Munster, Leinster and Ulster and three Scottish teams.
Four pools of six will clash over five weekends during the autumn international and RBS 6 Nations windows with the semi-finals and finals staged on April 24 and May 15.
The Rugby Football Union's tournaments and competitions director Terry Burwell said: "This is an exciting new tournament.
"It will provide quality cross-border competition and will be a winner with players, coaches and fans.
"There is a real appetite for this competition and, from an English point of view, it will give Championship clubs an additional meaningful competition alongside their league structure."
Welsh Rugby Union head of rugby performance and development Joe Lydon added: "This will benefit the development and sustainability of the professional and semi-professional sport in Wales."
Pools will be based on travel/geography with the aim of maximising local interest with the winners progressing to the knockout stage.