England rugby chief Nigel Melville has called on the Six Nations to condense by one week once every four years to safeguard the British and Irish Lions' future.
The Rugby Football Union (RFU) interim chief executive Melville has proposed his preferred solution to the Lions' preparation battles for the 2021 South Africa tour.
The Gallagher Premiership's reshaped future seasons put the English club league's 2021 play-off final on 26 June, just a week before the Lions' opening tour match in South Africa.
Pro14 bosses have already admitted they would reschedule their final once every four years, though Premiership chiefs have held onto their scheduled date - leaving stand-in RFU boss Melville putting forth another solution.
As it stands, the five rounds of the Six Nations are played over seven weeks with breaks after rounds two and three.
"Take timetables, my view is you can solve that problem," said Melville. "They (the Lions) need an extra week.
"If every four years we move the Six Nations from seven to six weeks, you create that extra week. So every four years why don't we do that?"
Lions bosses fought against the odds of a densely-packed schedule to pull off a drawn series with New Zealand in 2017.
But that left then-head coach Warren Gatland and tour manager John Spencer insisting only extra preparation time would keep the much-loved Lions alive.
The Lions' 2021 tour has already been cut from six to five weeks and 10 to eight matches, as part of global calendar reshaping agreed in San Francisco in January 2017.
The 2021 Premiership final has raised fears England players involved could simply be overlooked for Lions selection, given their lack of preparation time.
Asked if condensing the Six Nations would threaten player welfare, Melville replied: "No, because that week wouldn't have a game. It would be better preparation for the Lions so they have that week off, as in preparing. So you're saving a week here and putting it there.
"Instead of coming out of a final and going straight into a Lions tour, how about you have the extra week? That would make a difference.
"Is it better use of that week. That's the kind of solution that could probably solve that."
Melville urged all parties to be "creative" in solving this problem, but also conceded England would need to convince the other five unions in the Six Nations.
"There's only so many weeks in the year so we've got to get movement in that fourth year," said Melville.
"That's an opportunity to get that movement if Premiership weren't prepared to move.
"Or if they did, we'd have to have another overlap game, which wouldn't help anybody. It's another way of looking at it. Be a bit more creative.
"It would require the support of Ireland and Scotland and Wales, France and Italy as well who have no stake in the Lions.
"I'm sure the Lions could look at other options and talk to Premiership Rugby about how they can move it. Maybe there's an easier solution.
"It's more in our hands than in PRL hands. In my new role I'm on the Six Nations so I can certainly discuss it.
"The Lions is incredibly important for rugby. Is it worth fighting for? Of course it is."