Mark Webber says the depth of world class drivers in Formula One "has never been weaker" than it is at present.
The Australian left F1 at the end of the 2013 season, moving across to the World Endurance Championship to drive for Porsche. While there are currently five world champions on the grid - Sebastian Vettel, Lewis Hamilton, Fernando Alonso, Kimi Raikkonen and Jenson Button - Webber believes there is a big difference in quality between the front and back of the grid.
"These guys are on a phenomenal level but the depth has never been weaker," Webber told BBC Radio 5 live. "We need to get the calibre that we have at the front of the grid. We need more depth and the cars to be faster.
"If you go from the top 10 back, there are a lot of pay drivers. This is not good."
And Webber says one way of improving the calibre of driver is by making the cars harder to drive than they currently are.
"The physical components are the lowest it's ever been. It's like a rugby tackle but 30% softer ... The drivers want cars that are more demanding.
"It's a bit like being an F-18 fighter pilot but flying for British Airways. They're within their comfort zone, pacing races. It's frustrating. F1 should be the pinnacle. It should be by far the fastest through the corners, physical on the drivers and things where the drivers are the gladiators again.
"The car still needs to be something the fans have never seen anything like before. There's so many categories which are close to them now."
Click here for F1i's driver ratings from the Italian Grand Prix
2016 F1 driver line-ups so far
F1 drivers' girlfriends gallery
Keep up to date with all the F1 news via Facebook and Twitter
