The episode tries to show that even though the two pairs are on opposite sides of the law, they are quite similar in many ways. The basic plot involves the safeguard of a visiting foreign leader and, as such, is hardly imaginitive BUT this is merely the backdrop to the real story.

That said, the action scenes are terrific and there is a fair degree of humour during the Lads' training excercises.

Excellent performances by everybody here (particularly Michael Coles as Rio and Ian McCulloch as Macklin) and that makes it an even better episode, of course.

The story is very well put together: scenes of Cowley putting Bodie and Doyle through a defence drill cut to similar scenes of Rio training his men to attack. This idea is repeated where both pairs are having their "bedtime chats". Very effective and allows us a peek at the characters' backgrounds: Doyle talks about his time as a "tearaway" kid and how he joined the force to "get some discipline". Meanwhile Joe and Frank, hidden away in the loft, talk of their tough times as youngsters, too.

Some great humour here, too, though: With the possibility of death on their minds, Bodie warns Doyle that Heaven won't be Paradise if Cowley is there as well!

Much of the scripting, as we would expect from Brian, is excellent. Bodie: "Are you scared?" / Doyle: "Yeah. You?" / Bodie: "Yeah... all the time." – simple but effective.

The final scenes are the usual explosive action and Bodie finds irony in the fact that the killers used the outlawed dum-dums – something which he had previously suggested he and Doyle should use.

"I believe in me, 'cos I was born tall, dark and beautiful.... and engagingly modest, of course!"

The editing is incredible. The cuts from one pair to the other, in places even allowing dialogue to overlap makes for almost poetic parallel structure. Again, I am aware of the plot problems – ones I would never allow myself such as the possibility of the meeting at the pub and the brawl, but the overall effect is so good I forgive the flaws.

The entire sequence with Macklin is a true Pros jewel. Bodie in a tee-shirt is a rare treat! And Doyle in red then orange with the necklace – ah. Gorgeous close-ups, amazing use of props as symbols (one does hope that was unintended, particularly in the instance of the gun and cup – though it works at many levels!) and dialogue allowing us insight into the characters rather than merely advancing action. Marvelous, marvelous material.

The "night-before" scenes run a close second if not a tie with the above. We learn more about Bodie and Doyle in a few lines of dialogue than we have in all the shows that have aired before. Again, the direction, editing, acting, writing and camera work is all incredibly good.

Whoever decided that Doyle should wear sunglasses during the finale was a genius! To have both of them so emotionally vulnerable during the "you scared?" confession scene and to cover Ray's give-away eyes was pure art. Bodie can always keep his feelings hidden. With Ray the glasses were needed.

More parallel structure: Doyle shaving, surprised by Cowley and drawing so fast it has to be played over to catch that he uses his left hand and Bodie sitting watching the machine by the stairs and drawing his weapon in less than a heartbeat when Doyle and Cowley enter. The "guns fussing" scene with both pairs. Wonderful camera work.

Toward the end the scene showing both agents as watchers: they've never looked more "real". They prowl like panthers on guard. Perfect work by all concerned.

The Bodie-recognition moment is a classic. No one goes from friendly to deadly as quickly or as effectively. Again this episode shows us who these men really are!

Ray Doyle at the end, having killed his opposite, is a dirge made visible. He passes by the body without a glance and hunkers down by the water (wash my sins away?) to contemplate his weapon. It would be easy to imagine the character resigning from CI5 at the next opportunity, only to be talked out of it by his partner. One cannot exist without the other. By now their need for the balance they give each other is so great it's impossible to imagine them alone ever again.

Far and away my favorite episode. It's a brilliant piece of television art.

The first meeting venue is Brockett Hall, Lemsford near Hatfield. It had previously been used as Steed's place in the second season of The New Avengers. In real life the Hall was once used for high-level security conferences, being kitted out with a bullet-proof and sound-proof room made of glass to prevent the planting of bugging devices! In the 1980s Lord Brockett built up a classic car museum at the Hall but was later found guilty of fraudulent insurance claims against "stolen" vehicles. (Thanks to Tony Mackay and Sue Henschkler)

Rio says that after the pay-off Frank will be able to buy a couple of Rolls-Royces. Frank replies "Always fancied a Ferrari myself." Brian Clemens, who scripted this story, is a big fan of Ferraris!

Michael Coles played one the Thaals in Peter Cushing's first Doctor Who theatrical adaptation. He starred in a couple of early 70s Hammer horrors and the vicious leader of a team of hitmen in the first Sweeney movie (plus a spot in a regular episode). Very rarely seen on TV thereafter and passed away in 2005.

Ian McCulloch (Macklin) is best remembered for his long stint in Survivors. But his fortunes flagged and he ended up in a series of extremely gory horror flicks, some of which I believe were banned in the UK.

Nickolas Grace (Joe) is best remembered as the sherriff in Robin of Sherwood. Also starred in the classic mini-series Brideshead Revisited and alongside Martin Shaw in The Last Place on Earth. More recently seen as an ineffectual MP in The Final Cut. Otherwise he seems a rather busy theatre actor.

Mark Wingett (punk) will be instantly recognisable to fans of The Bill.