An elimination qualifying system was used at this season's first two races but met with widespread criticism.

Jean Todt, president of governing body the FIA, and F1 commercial boss Bernie Ecclestone have now agreed a return to last season's format is "in the interests of the championship".

It could be in place for next week's Chinese Grand Prix.

Todt and Ecclestone had been adamant there would be no return to 2015.

But their hand was forced by a unanimous stance from all 11 teams, saying they would not back another new proposal.

Why did teams make a stand?

Todt and Ecclestone had said at last weekend's Bahrain Grand Prix that they wanted to try out a new aggregate system that would see each driver's two fastest laps count for their grid position rather than just one.

This was initially proposed at a meeting between the teams, Todt and Ecclestone on Sunday, after the elimination format produced long periods of no action on track for the second race in a row.

But the teams decided enough was enough and insisted in a letter sent on Thursday that the new proposal added unnecessary complexity.

They said they would only back a return to the 2015 system, which this year would mean three knock-out sessions with the six slowest cars eliminated at the end of the first two before a shoot-out for pole between the 10 drivers remaining.

Why did Todt and Ecclestone back down?

The teams handed Todt and Ecclestone an olive branch by offering to look into a change of qualifying format for 2017.

Their dual position was enough to force Todt and Ecclestone to back down.

The FIA released a statement on Thursday saying that "in the interests of the championship" Todt and Ecclestone would "submit a proposal… to revert to the qualifying system in force in 2015".

This still has to be passed by the final two stages in the legislative process, the F1 Commission and the FIA World Council, but an FIA spokesman told BBC Sport he was "optimistic" it would be approved and that the 2015 format would be used from the next race in China on 15-17 April.

The statement added Todt and Ecclestone "welcomed the idea put forward by the teams to have a global assessment of the format of the weekend for 2017".

How did this all start?

What has turned into what many F1 insiders regard as an embarrassing fiasco started when Ecclestone told the teams less than a month before the start of the season that he wanted qualifying to change in an attempt to spice up race weekends by jumbling the grid.

He proposed two options: a shuffling of the grid after qualifying on the basis of some form of performance penalty so the fastest cars did not start at the front; or the new elimination system, where the slowest car is eliminated after 90 seconds through three sessions of qualifying.

The teams did not see the need to change qualifying but decided not to oppose the plan on the grounds that there were other more important fights to win. They voted for the elimination system on the basis that it was, as Mercedes F1 boss Toto Wolff put it, "the least worst option".

Before the start of the season, the teams pointed out problems with the system that would lead to large periods of empty track at the end of each session, but they were ignored and the new system was voted through unaltered.

The teams' predictions proved accurate at the season-opening race in Australia, and the teams agreed to revert to the 2015 system, only for Todt to prevent that happening.

A second vote in Bahrain had the same result - this time with Ecclestone joining Todt in refusing to revert to the 2015 format.

But the teams' determination has forced F1's bosses to back down, in what could come to be seen as a seminal moment in the power struggle that has been waged at the top of the sport for some months.

(BBC)