This fly-on-the-wall documentary about the former Irish Green party leader and cabinet minister Eamon Ryan reminded me of the political satire The Thick of It – but without the cynical gags and hapless self-serving politicians. Even after you factor in the skewing effect of it being a favourable portrait, showing him in the best possible light, Ryan comes across as one of the good guys: principled, likable and extremely hard working. The film follows his final 18 months serving in Ireland’s coalition government as minister for the environment and transport before stepping down in 2025.

The title is something that Ryan’s 25-year-old son Tommy repeats over and over. “Forever … forever … forever.” Tommy is autistic and requires full-time care. When Ryan resigns from government, one of his reasons is to spend more time with Tommy. We see the pair of them at the allotment picking raspberries and walking the dog. But other than a quick glimpse of his wife, Victoria, the rest of Ryan’s family life is kept firmly behind closed doors.

Instead, the cameras trail him on the road, talking to angry residents of an Irish town submerged by flood waters (again), and hustling at the UN general assembly in New York and two Cop conferences. At his side is formidable media adviser Edel Hackett (Malcolm Tucker with morals), who sifts through the daily torrent of online abuse, harassment and intimidation slung Ryan’s way.

The film is lacking a little context: perhaps an interview or two with Ryan might have been helpful, giving some background to the Cop conferences and – for those unfamiliar with Irish politics – the ambitious climate laws he pushed through in office. Something on the general election wipeout of Greens in November 2024 would have been useful too. But no explanation is necessary watching Ryan’s crumpled crestfallen face in January 2025 as he packs up his ministerial office, watching Donald Trump’s inauguration on TV.

• Forever Is Now is in UK and Irish cinemas from 19 October