He also raised the idea of an extra Six Nations tournament if England cannot fulfil their autumn internationals.

England are set for two games in Japan in July - a tour "under threat" because of the coronavirus pandemic - and four home Tests in November.

"Maybe we could combine those in some shape or form," said Sweeney. "We could possibly go there [Japan] in October."

Speaking to BBC Radio 4's Today programme, he added: "That's one option, because obviously they'd rather host, they make more money when they host, and we'd come back and play our autumns [internationals]."

England are scheduled to host New Zealand, Argentina, Tonga and Australia in November. Sweeney said that "the assumption at the moment is those games go ahead" but the RFU is preparing for what happens "if we weren't able to travel to each other".

“We'd want to do something to fill our gap so we're looking at a range of different contingencies," said Sweeney.

"An obvious one is: Do you stage a Six Nations in the autumn but link it into the Six Nations the next year, and you have a home and away series?"

The 2020 Six Nations was suspended with England having one game to play, away to Italy, which is yet to be rescheduled. Three other matches in the championship have not been played - two for Ireland, against Italy and France, plus the game between Wales and Scotland.