England have been placed at a disadvantage for their opening World Cup warm-up match after France broke with established protocol by scheduling their team announcement for Saturday's Twickenham showdown on the eve of the game.

Confusion reigns over the jurisdiction for the first of two clashes between the rivals after World Rugby and Six Nations claimed the other body was responsible for the capped international.

Les Bleus have chosen to unveil their side at 4pm on Friday afternoon, 28 hours before the 8pm scheduled kick-off at Twickenham.

Under World Rugby regulations, the team and bench must be named 72 hours before a match starts unless there are tournament or tour terms in place, which usually set 48 hours as the deadline.

While England announced their side on Monday afternoon, France are trimming their 25-man squad to 23 and selecting a starting XV four days later.

World Rugby insist the game falls under the auspices of the Six Nations - but the tournament organisers are understood to be co-ordinating the disciplinary process and in-competition anti-doping programme only, leaving the rules governing the team announcement shrouded in doubt.

England are understood to be baffled by France's ability to delay naming their team until so close to kick-off in what is a clear break with protocol.

Unless an agreement has been signed between the two unions then the match reverts to the 72-hour deadline established by World Rugby, which France will have missed by nearly two days.

The French Rugby Federation may now face sanctions in the form of a fine.

The second of the two fixtures is staged in Paris on Saturday week.