Darren Jones here mixing up the form of the constitution ("unwritten") with its substance - in particular who can change it ("not Darren Jones unilaterally").
🚨 Darren Jones: officials repeatedly told me I couldn’t act ‘because of the constitution’ “I would often reply with, ‘The constitution’s unwritten. So if I decide to do something, it changes. Therefore, why can’t I do it?’” He tried to “abolish the Cabinet Office three times” but was “not allowed”