McLaren boss Martin Whitmarsh has questioned the number of pay drivers who are currently involved in F1, making the argument that it is preventing drivers with real talent from reaching the top of the sport.

A number of teams have been forced to take on pay drivers again this season while more experienced figures - such as Timo Glock and Heikki Kovalainen - have found themselves left without a drive.

Quoted by ESPNF1, Whitmarsh said the increasing number of paid drivers on the grid were bad for the sport as it was preventing fresh blood from making the move into F1.

"I think, personally, it's sad to have so many pay drivers in Formula One," he said. "The numbers have crept up, and while I'm sure it's good and exciting for those that can afford it, you would hope that in the premier form of motorsport worldwide that you wouldn't have to have pay drivers and that means there are some good young, professional drivers who can't get in and aren't getting in.

"If you look at the churn of drivers it's very low. One reason is because teams are conservative and don't take risks [with their line-ups] and the risks that are taken materialise in instant revenue for the team but don't materialise in driver potential for the future. It's sad to say, but the reason that some of those guys are pay drivers, not all of them, but the reason that some are pay drivers is because they are actually and fundamentally not good enough to be in Formula One."

Whitmarsh also added that the issue of pay drivers was having a detrimental effect on the championships below F1, where those with budget were also filling up places on the various grids.

"I think it's difficult in Formula One for us to say to some the teams that you can't have pay drivers because sadly they have become an important constituent of the budget," he said. "In the junior categories, having drivers that are around for four or five years because they can afford to be there just clogs up the system.

"If the top teams had to have a rookie then I think they'd be a fight over the good rookies at the bottom and they'd get sucked in because those competitive teams need them and they'd get accelerated through."