Ex-McLaren driver Michael Andretti has criticised Formula 1 for allowing spiralling costs and regulation changes to leave the sport in a "mess".
Andretti, who runs his own team in Formula E, told the US edition of Top Gear that the rules concerning the type of engine needed for racing is costing constructor's too much money.
He said: "They made a mistake allowing engineers to come up with all the rules and everything. I mean, it's still the biggest racing sport in the world, and it has a huge following, but they need to make some changes.
"They need to go back to the rules. They've made these things way too expensive. With this new engine, they've basically doubled the leases for what it costs customer teams to run these things. It's stupid money, and for what?
"Then of course you continually hear the complaints of the cars being too quiet, and that they're too easy to drive. They need to change the rules, get it back to where a F1 car is hard to drive, and it's faster than anything out there."
Andretti joined McLaren in 1993, but was replaced by Mika Hakkinen during his first season.
