Producer Alison Lumb battled the elements to put the finishing touches to Boy Meets Girl.

So, Alison, what do you think?” First assistant Ellie Gabrilatsou looms up out of the darkness, shouting over the wind. She's not enquiring about my catering preferences.

It is March 2008 and the unit is high in the Pennines, huddled at the base of an electricity pylon. It's very cold and wet. This is our fifth consecutive night shoot.

The opening sequence, in which Veronica (Rachael Stirling) and Danny (Martin Freeman) are struck by lightning and swap bodies, is in the can.

We have yet to complete the final sequence, with its special effects and intense dialogue. But there is a problem: the lashing rain won't match the material that was shot the previous night and the ferocious wind limits our options.

Morale still seems high, though - director Alrick Riley is cheerful and as Rachael emerges from beneath an umbrella, I hear her say: “Darling, I can't believe I'm saying this, but shouldn't you spritz me down?”

Inevitably, the main concern is safety. What Ellie is asking is “Shouldn't we wrap?” But if we
do, we won't have a sequence.

We can't shoot this in a studio, which means we would have to come back, but that would decimate the budget. I hitch up the hot-water bottle slipping down my waterproofs and try to think of something authoritative to say. Ellie says she will get back to me.

[Writer] David Allison had pitched his wild idea for a comedy drama to [ITV Studios' controller of drama, Manchester] Kieran Roberts. What if a guy was trapped in a woman's body? And what if the man was a chippy Northern shelf-stacker and conspiracy theorist, and the woman was an affluent fashion journalist? How would they cope with each others' lives?

[ITV director of drama] Laura Mackie and [ITV drama commissioning controller] Sally Haynes had greenlit the show on a single script in autumn 2007.

Pre-production started in January 2008. It worked well because of the impeccable quality of the writing.

The story constantly changes tone and pace, with numerous action sequences and special effects. Aspirations were high, the budget tight. Alrick was eager to take on the challenge. Sean van Hales' glorious HD photography took excitement up another notch.

But the piece would stand or fall by the central performances. Rachael Stirling had to capture Danny's mannerisms and personality, as he gradually improves at imitating her. Her performance is magnificent.

Martin Freeman had to show that scruffy Danny is really a glamorous, middle-class woman. We were lucky he took it on - his presence lifts the show to another level.

And my answer to Ellie's question? Our luck was in. The rain stopped. Grip Brendan Judge laid 80 feet of track over rain-filled craters and we lined up the final shot.

Boy Meets Girl
Production company: ITV Studios
Producer: Alison Lumb
Director: Alrick Riley
Executive producer: Kieran Roberts
TX: 9pm, Friday 1 May, ITV1
Project summary: Boy Meets Girl is a comedy drama which transcends the gender divide. Danny Reed's life is turned upside down when he is struck by lightning and wakes to find himself trapped in a woman's body

Alison Lumb: My tricks of the trade
A set of A5-sized scripts to avoid back problems and hernias.
An MP3 player loaded with Radio 4 podcasts for sleepless nights (or days). I'm off again in no time.
My new half-size hot-water bottle for night shoots (to avoid that prolapsed look).
A willingness to keep asking stupid questions. That is so much better than making ill-informed decisions.
Shoot up north! The crews are amazing.