There’s something missing from Gary Oldman’s trophy cabinet.

One of the most decorated actors of his generation, he won a best actor Oscar, Bafta and Golden Globe for playing Sir Winston Churchill in Darkest Hour, plus two Baftas for Nil by Mouth, which he wrote and directed.

Next month he could pick up his first Emmy award, for his role as Jackson Lamb in Slow Horses, a man who spends a lot more time insulting his MI5 colleagues than he does on his personal hygiene.

However, unlike those acting knights of the realm, such as Sir Anthony Hopkins, Sir Daniel Day Lewis and Sir Kenneth Branagh, he says that he has been completely overlooked by the honours system.

“I don’t know why. You should ask them. No nod from the royals, but there we are” he told the BBC.

In recent years, Oscar wins in major categories have tended to be quickly followed up with royal recognition.

Mark Rylance was knighted the year after he won best supporting actor for Bridge of Spies, while Olivia Colman, Colin Firth and Eddie Redmayne were all honoured in the months following their triumphs.

In fact, Oldman is the only British winner of best actor or best actress this century not to be the recipient of some kind of honour, but he strongly refutes any suggestion that he has turned one down, by repeating “no” four times in succession.

“Maybe it’s in my future,” he adds wistfully.

Oldman has not exactly been short of plaudits during a career lasting more than 40 years, in which he has played Sid Vicious, Lee Harvey Oswald, Dracula, Gotham City’s police commissioner Jim Gordon and even made a cameo as President Truman in Oppenheimer.

But for the first time in his career, he is part of what is becoming a long-running TV show. Apple TV+’s Slow Horses is about to start its fourth series and is a real genuine word of mouth hit.

Speaking down the line from Palm Springs, where he now lives, Gary Oldman shares how he describes the show to people who have yet to see it: “The sort of slightly shady, dirty side of espionage. It’s your PG Tips, Tescos version of it I guess.”

Slow Horses focuses on the agents who have been discarded or are in trouble with the British Secret Service, and have been left to rot at Slough House, an establishment run by Oldman’s Jackson Lamb, a character so shabby and dishevelled, that the actor has given a lot of thought to how he smells.

“He’s a whisky drinker, so obviously, that’s sort of coming out of the pores.

“It’s that stale booze and cigarettes and some B.O., a bit of underarm thrown in.”

Lamb’s trademark move is breaking wind. A lot of discussion goes into how many farts he should have each series, and what they should sound like. Season five does get off to a windy start.

“These are the conversations and email exchanges that you have with the director,” Oldman laughs.

“You know: ‘This one is on a leather chair, so it should be more robust’. We have these ridiculous conversations about the frequency.”

With chat like this, surely the knighthood is now secured.

Slow Horses is often described as the “anti-Bond” and Gary Oldman could have had an 007 past of his own. He turned down the chance to be a Bond baddie in the pre-Daniel Craig era.

“I was asked quite a few years ago,” he confirms, although claims to have forgotten which film it was.

“The Bond villain didn’t ring with me,” he says without a hint of regret.

His Slow Horses co-star Jack Lowden, agent River Cartwright in the series, is one of the names which gets mentioned during discussions on who could be the next James Bond, and Oldman has an idea.

“I’d like to see a sort of prequel with him (Bond) in the Navy or something and becoming 007.”

It is clear he has given this a lot of prior thought.

“Jack’s probably a little young at the minute, but he could be a young Bond coming up through the ranks.”

One hugely successful British film series in which Oldman did star was Harry Potter, playing Sirius Black, and there is something he would like to clear up.

“I know fans got terribly upset saying: ‘Oh he couldn’t be bothered’ and ‘he didn’t read the books’. That’s not true.”

The point which Oldman wants to clarify, is that when he started filming his role, JK Rowling was still finishing off the books, and everything was “shrouded in such secrecy that you could only read the current book and you could never know what the next chapter and the next episode would be.

“If I had been able to read the books, I may have seen that arc and I would have known where Sirius Black was heading.

“I would have maybe approached the character a little differently, but there were no more books.”

“So I have hopefully put that to bed,” he says with a flourish of which Sirius Black himself would have been proud.

It should be pointed out that Slow Horses is based on a series of books by Mick Herron and Oldman has read all eight.

Starring in a long-running TV series may be a new experience for Oldman, but it is not for another member of his family.

His big sister, Laila Morse made her acting debut at the age of 51, in the only film Oldman has ever directed, Nil by Mouth.

Since then, for almost a quarter of a century, Morse has, on and off, played Big Mo in EastEnders, returning to Albert Square once again this May.

Oldman is adamant that his sister has no problems with him now treading on her small screen turf: “She took a break and is back. I don’t see the show,” he admits, before adding with a laugh: “But then Mo doesn’t really look at my stuff either. I don’t think she’s running out to see Oppenheimer.”

Sadly, the idea of Oldman making a cameo on EastEnders holds no appeal to him.

“I don’t think that’ll be on the cards,” he flat bats, before continuing:

“But, we’re happy. She’s got the Square, and I’ve got Slough House, so we’re quite happy where we are.”

And with that there is just time for Gary Oldman to say that series five of Slow Horses has already been filmed and as for the future, he is “in it for the long run” if they want him.

Slow Horses seems set to bring him more honours, just perhaps not of the royal variety.

Series 4 of Slow Horses starts on Apple TV+ on 4 September