Brenda Blethyn on the end of Vera: "I thought, what if I've made a mistake?"

Jack appears at the door of the room in which we are to do the interview, followed by his human. Blethyn flops down onto the sofa and Jack immediately jumps up next to her. He rests his muzzle on her leg and looks at me watchfully.

Blethyn ostensibly bought Jack for her husband, Michael Mayhew, a fellow actor she met at the National Theatre in the mid-1970s and whom she married in 2010. She felt bad about spending months every year filming Vera in the north east of England and thought Jack could keep Mayhew company at their homes in south London and Ramsgate, Kent.

However, when Blethyn was filming the 14th and final series of Vera this past spring – which comprises two feature-length episodes – Jack joined her, hanging out at the film unit’s base with a young woman hired to look after him.

Blethyn, who is in nearly every scene as the irascible but quietly charismatic DCI Vera Stanhope, would return for lunch and be enthusiastically greeted by Jack. Occasionally she’d have time to do a puzzle, a habit that dates to childhood, when her dad would set young Brenda and her eight siblings puzzles. The dog and the puzzles helped keep her mind off the fact that she was about to hang up Vera’s famous green bucket hat for ever.

Although Blethyn is aware of Vera’s global fan base, she was still shocked by the outpouring of dismay when she announced that she would leaving after 56 episodes. “I suppose it’s partly successful because it’s a family show. There’s no gratuitous violence against women. It’s not titillating. There are always interesting themes – in the second of the two new episodes, there’s a story around private children’s homes and it’s quite shocking.”

It must have been incredibly hard to leave such a successful series. Blethyn nods. “Finishing any job after 14 years is a huge decision, but I wanted to spend more time with my husband. And Jack. None of us is getting any younger. I don’t want to travel, I just want to be at home. Which isn’t to say I’m retiring – I said yes to making a film with Andrea Riseborough almost as soon as I finished Vera.”

Did she manage to get through filming the final scenes without shedding a tear? “I couldn’t help thinking, ‘God, this is it!’ I had a lump in my throat. I was all choked up. And of course I thought, ‘What if I’ve made a mistake?’”

Blethyn admits she’ll miss the character – “probably a bit of Brenda has filtered into Vera; we’re both compassionate, we both try to do the right thing” – but is modest about her detective sitting in the canon of great fictional female detectives such as Prime Suspect’s DCI Jane Tennison (played by Helen Mirren) or Happy Valley’s Catherine Cawood (Sarah Lancashire).

“Jack! Sit still. Sorry, love. Where were we? Oh yes. What’s so great about Vera is that she’s not dependent on a romantic relationship. Bravo! I haven’t watched it yet, but I understand it’s the same with Ellis.”

I tell her that Ellis star Sharon D Clarke is the first black female actor to play the lead detective on British TV and that the first series has had excellent ratings. “Well, I hope that Vera helped open the door for all female cops on TV – including DI Ray [starring Parminder Nagra], which I’ve watched.”

Her favourite TV show of recent years is, however, Slow Horses – which makes perfect sense if only on a sartorial level, since Jackson Lamb, the boss of a bunch of sidelined M15 agents, is even scruffier than Vera, who famously wears that green hat, long coats and an array of old scarves.

“I loved Mick Herron’s books so much that I didn’t want to watch the adaptation on telly, especially when I found out that Jackson Lamb was being played by Gary Oldman. It made no sense to me because Lamb is described as ‘Timothy Spall gone to seed’ in the books. But then Kenny [Doughty, who played DS Aiden Healy in Vera until last year] and I thought we’d watch one episode, and we raced through them. I just loved it.”

Blethyn, who was born Brenda Bottle (she kept her first husband’s name after their marriage ended in 1973), didn’t have a TV growing up in Ramsgate – in fact, she didn’t have much of anything. “I had a happy childhood. We didn’t know we were poor, but we certainly knew the value of things. Everything we had was second hand and had to be saved for.”

She points out that she didn’t need piles of expensive presents as a child to have a happy Christmas. Her mother was Catholic and Brenda attended a Catholic school, but she wasn’t baptised and although she and her siblings went carol singing, it was mostly “to get some money”. She remembers being delighted one Christmas when she was re-gifted a cradle she’d received the previous year. “It had been painted and there were new clothes for the same dolls. It was lovely!”

These days it’s just Blethyn and her husband at Christmas and, at some point over the festive period, they will see their best friends Timothy Spall – whom she acted alongside in Mike Leigh film Secrets & Lies – and his wife, Shane. What do Blethyn and her husband do to entertain the Spalls? “They come to Ramsgate, and we fly a kite on New Year’s Day,” she laughs. “I don’t know why, but it’s rather nice. This year I want to volunteer at one of those dinners they put on for people who don’t have much. I could serve or wash up or something.”

Since being persuaded to help out in a one-act play when working as a secretary at British Rail, Blethyn has been devoted to the stage and screen. At 27, she studied at the Guildford School of Acting and at 30 performed at the National Theatre in London. She has since appeared in dozens of plays, TV shows and films, but without ever taking herself too seriously.

I ask about acting alongside Robert Redford and Brad Pitt in the 1992 film A River Runs Through It and she grins mischievously. “Oh, you mean Bob Redford? He was keen I get the Montana accent right, which I hope I did. And Brad – well, he was lovely. Like a normal fella. His dog was on set and his mum and dad would come and watch filming.”

As much as Blethyn enjoys rubbing shoulders with Hollywood royalty, she has no airs, graces or truck for awards – “it’s nice to be given awards, or to be nominated, but it’s no different to building a brick wall and someone saying, ‘That’s a lovely wall.’”

After all, this is the actor who wore a pair of £12 boots she found in a shop in Birmingham for the first four seasons of Vera and who has had the lack of vanity to not care about Vera being as dishevelled as Peter Falk’s Columbo. “People often tell me that detectives don’t look like Vera, but I always ask how often they’ve been in a police station. Never? Well don’t judge then!”

She says that she’ll be at home in Ramsgate in early January watching the final two episodes of Vera – as well as the accompanying documentary, Vera… Farewell Pet (Friday 3rd January at 9pm on ITV1) – and that she might even enjoy doing so. “It’s better since I’ve been doing Vera, but I’ve spent my life suffering from impostor syndrome. Because, at the end of the day” – Jack wakes up and tries to lick her face – “I’ll always just be Brenda from Ramsgate.”

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Vera season 14 will arrive on Wednesday 1st January at 8pm on ITV1. Previous episodes are available to watch on ITVX.

You can also purchase instalments from any series on Amazon Prime Video. You can buy the first of Ann Cleeves's Vera novels now.

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