Better Than Doing Porridge

The trial is on, and Barlow wants his conviction. The gang has a weak link in Ernie Johnson, a hardened career criminal, and Barlow has been holding a trump card for exactly this moment: something that might finally persuade Johnson to go straight, or at least to talk. It is a nice piece of casting that gives the part to Patrick Troughton, a few years out of the TARDIS, bringing a face the audience trusts to a man the audience should not.

Most of the hour sits inside the courtroom and its corridors, watching Barlow play the card at the right time. It is a different rhythm for the series: fewer chases and more patience, with a lot of attention on one man deciding whether the price of loyalty is worth paying. Gabrielle Hamilton plays Mrs Johnson, and Glynn Edwards's Principal Officer Madox keeps the order of the court.

Stratford Johns anchors it as Barlow, with Frank Windsor's Watt and Julie Hallam's Forest in support. The gang around Johnson is filled out by Billy Murray's Georgie Benson, Ralph Watson's Harry Grant, Frank Jarvis's David Morgan and Michael Lees's Desmond Wetherby-Jones. It is a cast that knows how to make a courtroom feel crowded. Tony Hoare and Elwyn Jones wrote it, Keith Williams directed.

The pleasure is in watching a senior copper work a room he cannot control. Barlow has the evidence and the trump card. The timing is his to choose. But the decision belongs to Johnson, and Troughton makes that decision feel earned, which is the whole trick of the hour. The episode trusts the audience to sit with the legal machinery and the human cost inside it, and it works. A courtroom hour with a real pulse, and the weakest link turns out to be the man with the most to lose.