R360, the proposed global rugby series targetting the game's top stars, has pushed back its launch date two years to 2028, raising doubts over the project's viability.

"The decision to shift our launch to 2028 is a strategic decision based on timing," said R360 board member and former England centre Mike Tindall.

"Launching under compressed timelines would not meet the standards we set for R360, nor would it deliver the long-term commercial impact that the sport deserves."

Eight leading Test nations, along with the British and Irish Lions, have banned any R360 recruits from combining the new venture with their international careers.

Australian rugby league's NRL has threatened any player who switches to R360 with a 10-year ban from its competition. Any player who had signed up for the proposed launch in 2026 will now have their contracts terminated.

In an email to players, seen by the BBC, R360 co-founder Stuart Hooper said he appreciated the news would come as a "shock to some, and disappointing for all", but reiterated the desire for a launch in 2028 and for R360 to become an established part of the rugby calendar.

However, sources in the English club game say the R360 founders are "panicking" and don't have the financial backing or players to launch.

R360's initial aim of an inaugural event in October 2026, with eight men's and four women's teams, had been put under pressure by organisers' failure to secure sanctioning from World Rugby.

After receiving more than 100 pages of plans from R360, the game's governing body had questions over the staging of the event and whether players would be released for international action.

The earliest that World Rugby could have ratified R360 was in June, just four months before the new circuit's planned start.

R360's decision to delay for two years means it will avoid attempting to launch in the same year as the men's Rugby World Cup and a landmark first women's Lions tour.

However the inaugural Club World Cup - an event that brings together the best domestic sides from both hemispheres that was accelerated by the threat of R360 - is also planned for 2028.

"As a Board we remain absolutely determined to bring R360 to life at full scale and with maximum global impact. We're building something bold and new that will resonate globally - and we cannot wait to show the world in 2028," added Tindall.