MANAMA (AFP) - Formula One teams gave a mixed welcome to new owner Liberty's five-point blueprint for the future following its revelation in Bahrain on Friday (April 6).

Champions Mercedes said it was a "good starting point, but more details are needed" while Williams boss Claire Williams declared she felt it was "time to crack open the champagne".

The long-awaited plan was feared as the possible cause for a breakaway series led by Ferrari and Mercedes, but Mercedes team chief Toto Wolff said he felt satisfied.

"I think I am taking a positive view of the day because now we know what Liberty's vision for the future is - and it is a good starting point.

"I think there is room for compromise..."

The headline key point was a planned budget cap, expected to be US$150 million (S$197 million) to be introduced as part of the new package in 2021.

"That is not really achievable," said Wolff. "But I think we can work with Liberty on that now."

The mooted budget cap did not include costs of drivers and team marketing, a factor that may allow the big-spending top teams to restructure their budgets to operate below the cap.

Wolff said Mercedes' budget was "more around 250 million" and a compromise was needed.

There was no early reaction from Ferrari after the day's two free practice sessions which ended with the Italian team's Kimi Raikkonen on top ahead of his team-mate Sebastian Vettel.

Both Ferrari and Mercedes have been reluctant to embrace radical changes to the sport, knowing that with the support of ruling body, the International Motoring Federation (FIA), the new owners can introduce their plan without the backing of all 10 teams.

The five key areas covered were control of budgets and revenues, a new structure for governance, sporting and technical rules, cheaper and louder engines and overall costs.

'GOOD DAY FOR WILLIAMS'

Wolff accepted the direction of Liberty's planned future for the sport, but stopped short of accepting it.

He told reporters: "There is no such thing as a fait accompli because you can always decide if you like it or you don't. I think this is the starting point of a dialogue.

"Chase used a sentence that is intelligent that says 'we have no exclusivity to good ideas'. We will be starting discussions.

"There are many ideas and proposals that have been either overdue or necessary or good, and then there are some that are very challenging and need details to really understand."

Asked if Mercedes would continue beyond 2020, when the sport's current "Concorde Agreement" ends, if the blueprint remained unchanged, Wolff said: "This is a set of ideas and concepts for 2021 that need refinement and understanding of the detail - and only then is it right for the teams to decide if this is something they like and wish to participate in. Or not."

Red Bull team boss Christian Horner said he hoped to see the plan finalised within "a couple of months".

"There's some big topics to deal with there: engines, budget caps and redistribution of prize fund. It's ambitious, but they've got to go for it. At least they've put a target down to say we want this nailed within a couple of months," he said.

"The bottom line is this is going to have a much bigger effect on three or four teams running at the front of the grid.

"The guys from P4 downwards are potentially going to get a lot of upside. So you should see some fairly happy faces down that end of the paddock." Williams was one of the happiest.

She said: "I came back thinking let's crack open some champagne... Personally, I'm delighted at the proposals they laid down.

"We hoped for change under our new management and they've presented change.

"It was an extremely good day for a team like ours.

"I'm sure some people aren't going to be very happy. There's always going to be winners and losers in this situation. Sometimes it's about compromise if we're to protect the future health of this sport.

"If we can get these new regulations then I know that Williams' future is safe."