Formula 1 sporting boss Ross Brawn has labelled the lack of podiums achieved by midfield teams in the last two years as “unacceptable”.

Force India’s Sergio Perez scored the only podium managed by a team outside F1’s leading three squads Mercedes, Ferrari and Red Bull in 2018 with a third-place finish at the Azerbaijan Grand Prix.

The same race the previous year produced another shock result as Lance Stroll took a podium for Williams, though those two occasions have marked the only times that midfield teams have finished on the rostrum since the start of 2017.

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Renault enjoyed its strongest season since returning as a full works outfit in 2016 by securing fourth spot in the constructors’, though it finished nearly 300 points adrift of Red Bull.

"They were practically racing in their own championship, with far too big a performance gap between them and Mercedes, Ferrari and Red Bull," Brawn said.

"As was the case in 2017, only once and significantly, on a very unusual street circuit like Baku, did a driver from one of those seven teams make it to the podium.

“Last year it was Lance Stroll in the Williams, this time it was Sergio Perez for Force India.

"Two podiums from a total of 123 is unacceptable, especially when it comes with an ever increasing technical and financial divide."

F1 hopes to solve the problem by implementing new regulations and a budget cap from 2021, with the aim of reducing team spending and help level the competitive playing field.

"It's a problem we are tackling together with the FIA and the teams, because the future of Formula 1 depends on it,” Brawn explained.

“There are various solutions on the table and we must all accept that we can't go on like this for too much longer.

"I don't mean to cause offence by referring to the 'other' championship, it's just a way of describing the situation and their battle was certainly thrilling.

“However, it's hard for the fans to truly get excited about a battle for eighth place.

"Having said that, congratulations to Renault for finishing fourth, confirming the progress it is making and to Haas, as finishing fifth in only your third year in the sport is a great achievement.”

Brawn also praised the achievements of Sauber following two difficult years, and the rebranded Force India squad, describing its recovery from administration as “one of the most important things that happened” in 2018.

"Sauber fought back after struggling for the previous two years, partly thanks to the talents of Leclerc,” he added.

“But a special word goes out to the men and women of Force India who worked hard all season without letting themselves get distracted by the serious problems that affected the company and threatened its very existence.

“I think that managing to keep Force India on the grid and assuring it a stable future is one of the most important things that happened in 2018.”