Lockdown begins five weeks early for me. Not due to Covid-19 but because, on 18 February, I become a dad. Welcome, Roscoe. I plan to avoid looking at email for the first month.

Three weeks later, on 11 March, I give in. Louisa Compton, editor of Channel 4’s Dispatches, wants quick ideas on coronavirus. I send her a barmy notion about shooting a film in one day, editing it in a week, and broadcasting seven days after filming.

It is 16 March, my 57th birthday. Louisa calls as I am driving Roscoe to hospital for a jaundice check (he turns out to be fine). Channel 4 likes the “in-a-day” idea, but can we shoot it one day and broadcast the following night?

Only a newsperson would ask this. Anna Hall, our creative director, and I confer – we just can’t do it justice in a day, but suggest a compromise: shoot on a Friday, broadcast the following Monday.

On 23 March, Britain goes into lockdown, and Channel 4 commissions the film. The Monday chosen for broadcast is 6 April. We have two weeks.

Our team at Candour Productions in Leeds evacuates the building and we quickly learn out how to use Zoom, to try to figure how to make this project happen in lockdown.

We need to get three types of material: footage that we will send shooting producer-directors (PDs) to film properly; footage that people will shoot on their phones, but set up in advance, with guidance and direction from us; and all the other user-generated content (UGC) that will be a surprise – it will be whatever people send in.

We bring in PDs we know and trust to work alone; they are based in Glasgow, Belfast, London, Wales, Norwich, Birmingham, Leeds and rural Yorkshire. A team of producers focuses in parallel on specific UGC sequences, while Harry Lock works through the night creating a public upload website.

Friday the 3rd dawns. I film the lack of rush-hour traffic on the A4, but much of the remainder of the day is strangely quiet. After two frantic weeks, all I can do is wait.

Someone sends in a video of Lean on Me – it’s brilliant. We check the rights and find that Bill Withers’ passing is on the lunchtime news. We send out an appeal for people to sing along to Lean on Me, and this becomes the last three minutes of the film.

Three weeks into lockdown, I feel like a naughty schoolboy driving to Leeds along deserted motorways.

We have 48 hours to cut the film, and a fantastic team of shift-working editors. The Other Planet in Leeds has given us all its edit suites, so we can cut socially distanced. PDs watch screens in other suites on Zoom.

Saturday 4 April. We’re way behind schedule; Channel 4 is worried – 3,185 clips have been uploaded by the public, and every single one has to be watched.

By the early hours of Sunday morning, we have a great part one – filmic, funny, beautiful, moving. Somehow, 30-ish hours later, the other three parts are just as good.

Monday 6 April, 2:00pm, I head for home. I’ve not slept much, but the adrenaline buzz gets me back to London safely.

Our absolute deadline is that the film has to be uploaded by 5:00pm, otherwise it will be dropped. At 5:21pm, I get a WhatsApp: “Red Bee confirms that it has a complete recording.”

At 8:30pm, 32 of us convene on Zoom for a pre-transmission party. Anna and I both make little speeches. Mine is to the effect that I had hoped we could pull it off, but, in the end, what we produced astonished me and is one of the best films I have ever been involved with.

Brian Woods is founder and director of True Vision (London and Cambridge) and Candour Productions (Leeds). A Day in the Life of Coronavirus Britain is on All4.