Richard Attenborough, the late Oscar-winning director and chair of Channel 4, would be “turning in his grave” to see the broadcaster privatised, his son has claimed. Michael Attenborough said that Michael Grade – Channel 4’s chief executive from 1988 to 1997, who will monitor the privatisation process as chair of the broadcast regulator, Ofcom – was breaking a promise to his father by supporting the sell-off. In a letter to the Guardian, Attenborough, who is a theatre director, said: “Perhaps Lord Grade needs reminding of the promise he gave my father, Lord Attenborough, when he was running Channel 4 and my father was its chairman. Namely that he ‘would die in a ditch before he’d see Channel 4 privatised or its public service commitment in any way diminished’. “My father must be turning in his grave. I only wish he was here to face, expose and oppose him.” He added: “Grade knows only too well that once profit becomes the prime motive, undertakings about risk, diversity, regional spread, grassroots commissions etc will inevitably be eroded and tragically disappear.” As chief executive and chair of Channel 4 respectively in the late 1980s, Grade and Attenborough fought off the first attempt by Margaret Thatcher to privatise the channel she herself had greenlit in 1982. Attenborough said he had written privately to Grade, a Conservative peer, to express his dismay and that while Grade wrote back quickly, he failed to properly explain his change of heart. “He used a phrase like ‘the landscape of the media has changed massively and it’s not just as simple as there being the famous four main terrestrial channels’,” Attenborough said. “But that doesn’t really explain anything. He’s of course right – the landscape has massively changed. What I don’t understand is why the rationale behind this unique creation, Channel 4, needs to be altered.” He added: “I have openly said to him, Michael, you have betrayed everything that you went out and stood for and everything that you and dad fought for: how could you do such thing?” Channel 4 is unique in being publicly owned, thus retaining its independence, and with a public service remit. Attenborough said: “To turn it into a private enterprise, to privatise that, seems to me to be a direct contradiction of its inception. I’m absolutely bewildered by it. There are very few people on earth who can say they knew my dad better than I did and I am absolutely sure he would be spinning in his grave.” In a column for the Mail on Sunday, the culture secretary, Nadine Dorries, who is leading the privatisation process, said Channel 4’s state ownership was a “restrictive incongruity in itself on to the scene, with juggernauts such as Netflix, Amazon Prime and Disney+ upending the old order”. She said Netflix spent £779m on UK original productions in 2020 – more than twice as much as Channel 4. She also criticised Channel 4 for decreasing the amount it spent on new content by £158m “at a time when it should be investing in new programmes, technology and skills”. The Channel 4 board said in its 2020 annual report that it made the cuts during a period of huge uncertainty owing to the coronavirus pandemic “to ensure liquidity and safeguarding of the business through a wide range of situations”. Dorries said those criticising her were the “leftie luvvie lynch mob” and claimed that there was “no reason” the sale couldn’t result in more of Channel 4 moving north out of London.