Thursday, 16 February, 2012

To Manchester where I am to have a walk-on part in a new TV version of my first novel, A Very British Coup, about the overthrow of a radical, very left-wing prime minister. Not that this new series bears much resemblance to my book. Even the title has been changed – to Secret State – and the credits say "inspired by" rather than "based on".

Director Ed Fraiman has kindly agreed that I might have a walk-on part, a la Alfred Hitchcock. I thought he might reincarnate me as a backbench MP or even a minister; instead I am to be the vicar conducting a memorial service for the deceased PM (there is no body: he died in a suspicious plane crash).

I find myself sharing a car with Charles Dance and Gina McKee. Gina, it turns out, is the daughter of a Durham miner, who for a time lived in Sunderland, about a mile from where I live. We are driven to a leafy part of Cheshire popular with Premier League footballers and delivered to a trailer encampment alongside a decaying walled garden.

Each actor is allocated a dressing room. There is a pecking order. The biggest stars get the swishest trailers. I share a small room with an actor who is playing a political correspondent. Each door is labelled with the screen name of the occupant. Thus the dressing room of Gabriel Byrne, the lead actor, is labelled with the name of the deputy PM, Tom Dawkins. The label on my door simply says: "Vicar."

A young woman from costume instructs me to don the uniform hanging in the wardrobe. It's the full monty: black suit, cassock, white surplice, purple stole, dog collar. Next she produces a bag of polished black shoes and invites me to select a pair. Finally, I am supplied with a watch. All vicars wear watches, it seems. Then makeup is liberally applied to prevent my bald forehead reflecting the light.

At 8am, we are driven to a 14th-century church in Nether Alderley, where we are to film the memorial service. The church noticeboard informs us that this is the constituency of George Osborne, who is, he says, at the disposal of any of his constituents, regardless of how they voted. The rectory was once the home of Neil and Christine Hamilton – until they met their nemesis in the shapes of Mssrs Mohamed Al Fayed and Martin Bell.

We are shown into the green room, a schoolhouse. The actors, all old hands, know each other by sight, if not by name. Charles shakes hands with Lia Williams. Her face rings a bell, but he can't quite place her. "Have we worked together before?" "Yes," she replies. "In Birmingham. I was your wife." Today she is the head of MI5. Charles is the chief whip.

I am to stand at the church gate and greet mourners. When the grieving widow arrives, I am to take her hand and accompany her to the church door. Next to me stands Rupert Graves. He is a senior member of the government, but he is not sure which. He buttonholes a passing production assistant. "One question: am I the Chancellor or the Home Secretary?" The scene is shot repeatedly, perhaps 10 times. Then we move to the church door where I am to greet Gabriel, the acting PM, who sweeps down the path accompanied by stony-faced protection officers and the head of MI5, with whom he is in a whispered, deeply serious conversation. The party is preceded by a camera crew, walking backwards. When they reach me, the scrum miraculously parts, conversation ceases, and Gabriel looks at me meaningfully. At this point, I am to utter the first of my four humble sentences: "Hello, Charles always spoke highly of you." Charles is the dead PM. Gabriel replies: "Thank you, vicar."

After four or five takes, I make so bold as to point out that it's not very likely a vicar, confronted with the acting PM, would simply say: "Hello." How about: "Good morning, sir"? At first this meets with resistance, but eventually it is decided to shoot both versions. I wait to see which, if any, survives.

My cassock was designed for a taller man than me, with the result that, to walk anywhere, I have (to use a suitably biblical phrase) to gird my loins. Occasionally, I forget and find myself entangled. At the first speck of rain, someone appears with an umbrella. From time to time, a woman sprays my hair with lacquer, while someone else brushes the mud from my cassock. Yet another person – from continuity – snaps away with a digital camera.

And then it is my turn again. I have to wait in the porch until everyone is inside the church, count to 10 and then make my way to the front, pausing to shake hands with a couple of mourners. I now find myself at the lectern, facing the congregation, preparing to spout my remaining three lines. A tricky moment. Though I have learned them by heart, I am in fear of drying up, thereby destroying what is shaping up to be a promising acting debut. Happily, the director slides the relevant page of the script on to the lectern in front of me. As a result I am able to deliver my lines with confidence – and without much more than a downward glance. It is all over in a single take. Amazing.

Everyone is very kind about my performance, but later the doubts begin to seep in. The hour was late and the director was anxious to wind up. Perhaps he has already decided to drop the scene, but can't bring himself to tell me. I shall have to wait until autumn to find out.

Saturday, 20 October

I have been sent a preview. Gabriel looks suitably grave and prime ministerial. Charles is suitably sinister. Gina is radiant as the whistle-blowing journalist. It races along with great speed and credibility. Soon we are at the memorial service. And sure enough, there I am in my full vicar's gear. The camera lingers for all of five seconds. And that's it. Gone is my much-filmed walk to the church door with the widow. Gone my brief exchange with the acting PM. Gone my three precious sentences praising the dead PM. (Gone, too, a 20-strong choir.) So that's it. My acting career lasted all of five seconds. But, hey, who cares? It's a great film.

• Secret State starts on Channel 4 at 10pm on 7 November. Chris Mullin's novel, now titled Secret State, is published by Serpent's Tail, price £7.99 and is out now.