This may be a record. Our independent documentary film has run for four weeks in the West End of London, with four screenings a day, and continues to be picked up by London cinemas, including many which originally turned it down.

It is booked in cinemas around the country until the end of September.

As a writer and not a habitual film-maker, I had no idea how impressive that was, but Christopher Hird, our executive producer, tells me that nobody can remember another UK produced documentary having anything like this success.

Only An Inconvenient Truth had anything like this impact, and it had tens of millions of marketing money behind it that we have not.

What has astonished even us is the way the film has broken out of the usual circle of dedicated followers of the environmental cause and found its way into the consciousness of the public at large.

It has been taken up by the Sun, Hello and Heat magazine, as well as regional and local papers and the entire national press.

It has also engaged with the corporate world in ways no one can remember any other British film doing. The head of a major High Street presence, Pret a Manger, saw an early screening and changed his entire company’s policy on tuna.

I notice that even Morrisons, which was at the back of the pack, is now advertising some of its fish as line-caught.

The fact that the film has struck such a chord with the people and companies who have seen it has put the issues in the film on the political agenda, in ways they were not before. We can report that the fisheries minister, Huw Irranca Davies, asked to see us.

I went along to a very amiable meeting accompanied by Greta Scacchi, our fish ambassador. I shall be at a screening for officials at the Department for the Environment, Food and Rural Affairs this week.

We have met the Tories, who have asked the Government some searching questions in the Commons about whether it will support an immediate ban on fishing for bluefin tuna in the Mediterranean, the population of which appears to have collapsed.

We even have an appointment to see Downing Street officials, as a result of Sarah Brown’s championship of the film. I have already debated the reform of the Common Fisheries Policy with Joe Borg, the European fisheries commissioner.

So it is amusing that the only person who has not made time in his diary to see us or to debate the issues in the film is Richard Lochhead, the minister responsible for fisheries in the Scottish Government.

The organisers had hoped that Mr Lochhead could see the film and debate the issues with me at one of our Edinburgh screenings.

But his officials could not find a single moment in his diary during the week that the film was in town for this to happen, nor could they put up a junior minister or senior official to debate Scotland’s handling of fisheries or its home-grown variant of the Marine Bill.

We know that the Scottish National Party derives much of its support from fishing constituencies, in other words is scared stiff of the fishermen’s vote. Many had hoped it would take a more rounded view while it was in office.

But I think this failure to show up and debate a film that has caught the public mood shows a disturbing inability on the part of Scotland’s government to deal with how devastated Scottish and European fisheries actually are, a contempt for the majority of citizens who are not fishermen, and an ostrich-like belief that the issue will somehow go away.

I assure them it will not. Indeed our campaign is only just beginning.