Line of Duty: From waistcoats to acronyms, why we love the BBC show

Jesus, Mary and Joseph and the wee donkey (to quote Superintendent Ted Hastings) – it feels like Line of Duty has just returned to our screens and now its finale is just one day away.

The hit police drama has kept fans gripped since it first burst onto our screens back in 2012.

Last week’s penultimate episode of series six earned an average of 11 million viewers.

And tomorrow night’s finale will have them all waiting with bated breath as the search for ‘H’ – the corrupt officer responsible for a mass conspiracy – comes to an end.

There’s plenty of reasons it’s become such compulsive Sunday night viewing – and here are just a few of them:

1 Mastermind writer

Top marks to Jed Mercurio. The TV screenwriter gives viewers 60 minutes of twists and turns and thrills and spills – every episode is a rollercoaster ride and a half.

Suspense, tension, revelations and cliffhangers leave fans turning detective themselves as they try to work out the good cops from the bad cops.

Former Cannock schoolboy Mercurio also provides the shock factor. He’s never scared to kill off any character. We just get to know them and then they meet an untimely death.

No one is safe in Line of Duty and that makes it all the more gripping.

2 Stellar Cast

The immensely talented Vicky McClure, Martin Compston and Adrian Dunbar are the show’s veteran trio in the roles of DI Kate Fleming, DI Steve Arnott and Superintendent Ted Hastings.

They have been joined by plenty of guest stars over the years – such as Thandie Newton, Keeley Hawes, Stephen Graham and, in the current season, Kelly Macdonald.

It’s also fabulous to see so many characters return down the line. Halesowen’s very own Gregory Piper was in season one and returned in five and six as one of the drama’s greatest villains.

And it’s not just the fast pace action and quality one-liners we love them for – the brooding stares and suspicious glances also keep us all transfixed.

3 Ted Hastings and his catchphrases

Ted puts the super into superintendent. The man who heads up AC-12 is everyone’s favourite gaffer. Every episode the no-nonsense chief brings his dry sense of humour into the drama with his one-liners.

Mother of God is an oldie, but it remains one of the most iconic ‘Tedisms’, as fans refer to them. When he mutters those words you know something serious is going down.

Another iconic line that sums up his passion for the job is: ‘There’s only one thing I’m interested in and that is catching bent coppers’ and when he’s defending his team he makes it clear his officers ‘conduct themselves to the letter of the law’.

Another favourite is when he introduces himself as ‘Superintendent Hastings, like the battle’.

A recent addition to his iconic sayings came last week with the ‘Jesus, Mary and Joseph and the wee donkey’ line he used in response to DCI Jo Davidson’s ‘no comment’.

Oh Ted, if there’s no series seven we really are going to miss you.

4 Steve Arnott's waistcoats

Waistcoats are as much a part of DCI Steve Arnott as the words Mother of God are for Ted Hastings.

He’s always in a dapper three-piece suit. He was rocking the look way before England manager Gareth Southgate sent sales of waistcoats soaring due to his World Cup outfit.

Just a shame they haven’t created a bullet-proof waistcoat for Steve – yet.

5 Police lingo

Line of Duty acronyms and abbreviations are as iconic as Ted’s sayings. And this season we’ve had an overload of police lingo.

OCG is one of the most common terms and has been in the spotlight from the start, it standing for Organised Crime Group. But this season also gave us CHIS – a Covert Human Intelligence Source, in other words an informant (but it would be boring just to refer to it as that).

Other popular ones include SIO - Senior Investigating Officer and MIT - Murder Investigation Team.

6 Interrogations

It starts with a Digital Interview Recorder (or DIR for those who know the vocabulary, see above) and what sounds like a never ending beep – it can only be a Line of Duty interrogation scene.

Tension is as tight as one of Steve’s waistcoats in these AC-12 interviews, because you never know what’s coming - well other than the ‘I’m entitled to be questioned by an officer at least one rank superior’ and ‘God, give me strength’ lines.

Roll on tomorrow night. We’ll be sucking on diesel once we find out who H is.