At least we can count on Line Of Duty to serve up a jaw-dropping final episode

Millions of viewers will be on the edges of their seats tomorrow for the final episode in this series of Line Of Duty on BBC1 – a thriller that’s given us more twists and turns than a Strictly Come Dancing routine. Online forums are buzzing as people predict the identity of ‘balaclava man’, who’s believed to be responsible for murders, abductions and throwing DS Steve Arnott down a stairwell. Whatever happens, it will be a jaw-dropper.

Ever since it started five years ago, Line Of Duty has delivered a masterclass in knock-yousideways endings, leaving its audience satisfied, entertained and yet gasping with incredulity at what they’ve just watched. A drama not afraid to kill off major characters played by wellknown actors – Jessica Raine was hurled from a window and Keeley Hawes had her brains blown out – is a rarity and what sets Line Of Duty apart. And that’s exactly how it should be. Nothing matches the disappointment of a fantastic show bowing out with a daft, implausible or untidy ending.

Many fans were concerned that the finale of the last ever Broadchurch would be a damp squib. Although the first series was sensational, the second was best forgotten. However we needn’t have worried – it went out in a blaze of glory with an ending that floored us couch detectives.

We’ve been spoilt for choice when it comes to cracking endings recently. The final instalment of Homeland served up shocks and a cliffhanger, leaving fans desperate for the next instalment.

When it comes to disappointing finals, special mention goes to the BBC’s recent series The Replacement. It was an absolute corker of a psychological thriller that, alas, totally unravelled in the last 20 minutes.

The longer you stick with a TV series the more galling when it departs leaving more questions than answers. Ten years after the last episode of The Sopranos, fans are still divided over whether it was a stroke of genius or a cop-out that it was left in the air whether Mafia boss Tony Soprano would be shot dead in a diner. Perhaps the series that will go down in history as having the most disappointing ending ever is Lost. Those who had stuck with it for six seasons were left to try and fathom whether all the characters had been dead all along.

So I have every confidence that, as the curtain comes down on Line Of Duty, it will do its duty to the audience at home and go out with a decisive, dramatic bang that will leave us longing for the already commissioned series five.

Line Of Duty, tomorrow, 9pm, BBC1. MY VIEW