Emergency services were called to the collision northbound at junction 8 near the M25 at about 11.40am.
Surrey Police said the crash involved two lorries.
One of the drivers was treated by paramedics at the scene and has been taken to St Georges Hospital with serious injuries, police said. The other driver sustained minor injuries.
Two lanes are currently closed while emergency services deal with the incident. There are significant tailbacks and motorists are being advised to take alternative routes.
“The closure will primarily affect traffic heading away from Gatwick Airport,” a spokesman added.
Anybody who witnessed the collision is asked to call police on 101 quoting P16198935.
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