Lord Sugar is departing as chairman of YouView, the internet set-top box company which is backed by the BBC, BT, ITV and others, amid rumours of tension with some of the shareholders.
The Apprentice host will leave “in the next few weeks” after only two years in the non-executive, part-time role, which earned the multi-millionaire mogul £500,000 last year.
YouView has not lined up a replacement and will name a successor “in due course”.
One well-placed source said that Lord Sugar's famously robust manner in front of the cameras on The Apprentice TV show was not so different when he was chairing the joint venture whose other shareholders are Channel 4, Channel 5, TalkTalk and Arqiva.
A YouView spokesman declined to comment on suggestions that there was any tension in the boardroom.
Lord Sugar said in a statement: “When I joined YouView in 2011, my brief from the shareholders was to use my experience in the electronics industry to get the product to market and into the homes of consumers.
”Having done that successfully, my job is complete and I will now focus my time and attention into my other businesses.“
YouView allows viewers to watch live, record and catch up on any TV programme from the last seven days on all the free-to-air TV digital channels through the internet-enabled set-top box.
The venture was much-delayed when regulators opposed a previous incarnation, called Project Kangaroo, but it eventually launched last summer.
A spokesman claimed that YouView is ”now the fastest-growing TV platform in the UK“, although few numbers have been released so far about the sale of set-top boxes, which retail at £299 each.
Lord Sugar is said to be worth £800m, according to the Sunday Times Rich List.