McLaren have confirmed they are to lose title sponsor Vodafone at the end of the season.
In partnership since 2007, Vodafone has decided "to focus on business priorities away from Formula One sponsorship" after exceeding "all the highly ambitious targets...set for its title partnership".
In their six years to date McLaren and Vodafone have enjoyed 34 grand prix victories, as well as winning the 2008 drivers' world title with Lewis Hamilton at the helm.
McLaren have confirmed they will announce what will be only the fifth title sponsor in their history on December 2, but will not disclose beforehand out of respect to Vodafone.
Team principal Martin Whitmarsh said: "We're immensely proud that, having been set a number of ambitious challenges by Vodafone back in 2007, together we've met or exceeded each and every one.
"Our focus is on continuing to drive results for all our partners throughout the 2013 season, and we look forward to making a major title partnership announcement towards the end of the year."