Filming had to end by lunch so Freddie could speed off to the pub

When I was asked to make a programme about the bestselling thriller writer Frederick Forsyth, I saw it as a chance not only to tell his amazing life story, but also to craft a portrait of a quintessential Englishman in the final years of his life.

I was also curious to know where, in his mid-eighties, his career and notoriously bullish character had left him. I had no idea when we started filming last October that it would be the final interview he would give before his death this year.

We started filming as the much-anticipated TV adaptation of Freddie’s multimillion selling The Day of The Jackal was approaching, and Freddie was in demand. When she wasn’t setting up his iPad for radio and podcast recordings, Michelle Welch, Freddie’s personal assistant and housekeeper, was fielding a steady stream of media visitors to his home. Despite his protestations about never getting a moment’s peace, he seemed to be enjoying himself, and said yes to almost all media requests.

Our first day of shooting was scheduled for the evening of the show’s premiere at the Royal Festival Hall on London’s South Bank. The plan was for me to film Freddie at the event. When I found out that Freddie’s wife, Sandy Molly, had died just days before, I offered to cancel, but Freddie was having none of it. He wanted to honour his commitment and dutifully turned up on the red carpet, despite his misgivings about the TV show: “A homosexual snogging match? I don’t remember writing that!”

The success of The Jackal TV series and Freddie’s decision to reveal Sandy’s struggle with opioid addiction meant the interview requests kept coming. For us as filmmakers, Freddie posed a challenge. He had told his story so many times that he was prone to trotting out familiar anecdotes. I wanted to find a new way to tell his extraordinary life story: his humble origins in Ashford and unhappy school days; becoming the youngest pilot to qualify for the RAF; his time as a foreign correspondent in Paris, East Germany and Africa; making millions as a writer, losing it all in a 1980s investment fraud and making it again.

Before we began our filming, I reluctantly agreed to finish no later than 12.30pm each day so Freddie could drive at breakneck speed to The Jolly Cricketers for lunch, red wine and The Telegraph crossword, before returning home for a nap. We agreed not to discuss politics – like his fervent pro-Brexit views or disdain for so-called “woke culture” – but to stick to the personal experiences that had shaped him.

My attempts to disrupt Freddie’s usual seamless storytelling by asking questions about his life out of chronological order were met with irritation. I also repeatedly asked Freddie how events made him feel. Never one for “flowery language”, Freddie struggled at first to find suitable adjectives, but as trust grew over our filming sessions a different Freddie emerged.

I found him to be a curious mix of generosity and impatience. While giving us free rein to film in his house and access to his wonderful personal archive, he would berate us over how much equipment we had and how long we took to do things.

After his post-pub nap, Freddie liked nothing more than to relax in front of his enormous TV and watch The Chase, his favourite afternoon quiz show. It was not unusual to hear him shouting at the stupidity of the contestants.

Despite a worsening shortness of breath, Freddie seemed to enjoy himself. There were some truly moving moments of candour, such as when he shared his deep regret at not being at the bedside of his dying father – he had been away on holiday when his father’s health deteriorated and was told not to return early.

The more we delved, the more he revealed himself to be a man of great complexity – one who had experienced so much adventure, excitement and success, but also one trying to remain resilient in grief.

At the end of last year, Freddie was diagnosed with chronic obstructive pulmonary disease, and in the spring he was diagnosed with small-cell lung cancer. By the time editing had finished in May, Freddie’s frail condition had continued to deteriorate, but he was keen to see the film. We hastily planned a viewing on the huge TV.

It’s always nerve-racking to show a contributor the film you’ve made about them, and we feared Freddie’s disapproval. Despite his obvious tiredness – he even lacked the energy to be grumpy – we watched the film together. “A+,” he declared when it was over.

Freddie died from cancer on June 9, aged 86.

Ben Anthony is the director of In My Own Words: Frederick Forsyth, which is broadcast on BBC1 on Tuesday at 10.40pm and afterwards on BBC iPlayer.