Lord Sugar's sidekick Nick Hewer is to leave BBC1 hit series The Apprentice after a decade.
The PR guru, who has worked with the businessman since 1983 when he began promoting the Amstrad brand, has been an adviser on the show since it started in 2005.
Hewer, 70, said he thought it was the "appropriate time" as his stamina is not what it was, but said his departure was with "relief tinged with regret".
He and Karren Brady keep an eye on the hopefuls and give feedback to Lord Sugar when he decides who to fire each week in the boardroom showdown.
His exit was announced as he filmed the final of this year's series, which will be screened on Sunday night at 9pm.
Hewer, who also hosts Channel 4 afternoon words and numbers game Countdown, questioned the abilities of the show's candidates last month and said they were "not the brightest business brains in Britain".
He said tonight: "I've been pondering my departure from The Apprentice for a while and have decided that year 10 is the appropriate time.
"I've enjoyed being part of this wonderful television series for two reasons: firstly, because it's been fun and has opened up many unexpected opportunities for me, but more importantly, because I think The Apprentice is a truly valuable programme, teaching young people the basics of business - not in a classroom setting, but in a wonderfully entertaining format.
"And the winners each year validate the value of the show - talented, creative and hardworking young people, all of whom are making a great success of their businesses."
He added: "So I leave with relief, tinged with regret. Anyone can do what Karren and I have been doing, but it takes stamina to follow the candidates week after week, and my stamina is not up to those long weeks.
"I shall continue to enjoy the show from my armchair, marvelling at the candidates' self-esteem, at the sky-high production values of the producers and at the extraordinary talent of my old friend Alan Sugar."
Margaret Mountford, who was his fellow adviser when the show began, stepped down in 2009 to be replaced by Baroness Brady.
Labour Party supporter Hewer, whose dry wit and spiky comments have made him a hit on BBC1's Have I Got News For You, went into public relations in the mid-1960s and headed his own company for 30-plus years until it was sold in 1997.
He has looked after Lord Sugar's public profile and has been a firm friend since they hooked up three decades ago.
Since launching his TV career on The Apprentice, he has also presented a number of shows including The Farm Fixer and The Town That Never Retired.
Sunday's final will be immediately followed by You're Hired.