F1 needs to get back to basics in order to spice up the show, according to Alain Prost.

Now a Renault advisor, the F1 legend and quadruple world champion is an avowed 'purist' who thinks the sport was better when the rules and cars were simpler.

"The engine rules are the most complicated," he told Ouest-France when asked about what Liberty Media should do to the 2021 rules to improve F1.

"Every change to the engine involves significant costs, but they should in any case be more powerful with more fuel available and more performance," said Prost.

And he thinks an approach based on simplicity would also work in other areas of the rules.

"Technically it should be simpler, giving rise to the possibility of surprise, ingenuity, and the driver making the difference, rather than these machines of war that we see today where 80 per cent of the performance is aero and engine.

"I would like to see a better balance," he said.

Prost doubts that the 2019 rule tweaks will make a big difference, arguing that the size of the modern cars is actually the main problem.

"Personally I would remove the diffuser. In my day we had different concepts with big performance and we followed each other with no problem. We need much simpler cars aerodynamically."

And he said the simpler rules of the past meant the sport was genuinely interesting because of variety.

"Over a year we had turbos, V8, V10, V12, Michelin, Goodyear, Pirelli," he recalls. "We cannot go back to the past because it's very complicated to have different technologies. But it's a balance of technology that makes the difference."