One of Our Pigeons Is Missing

Bulman goes undercover as a tramp, which is the kind of sentence that sells itself. A man sleeping in a doorway attracts no attention at all, which means nobody notices the detective inside the disguise collecting information. It is the oldest trick in the book, dressed in the oldest coat in the wardrobe. The premise sounds like a lark and plays like a proper investigation, which is the right balance.

But the title is a joke, and the episode knows it. One of our pigeons is missing sounds like a gentle parody of a spy thriller, and the show plays it straight enough to make the joke work. The humblest sources carry the best information, and a retired detective can always find a reason to set his dignity aside for a good cause.

Thorley Walters' Bill Dugdale drifts through the edges of the story, adding the familiar texture of the recurring world without ever stealing the focus. Murray Smith wrote the script and Charlie Nairn directed, and they are smart enough to keep the tramp act going long enough to be funny without letting it become a sketch. The disguise has to be believable, and Henderson makes it believable: the clothes, the walk, the way the voice changes register when he is in character. It is the kind of performance detail that rewards a second viewing.

Don Henderson commits to the disguise with a straight face, which is exactly what the part needs. Siobhan Redmond's Lucy McGinty does the straight-running, keeping the case moving while her partner works the streets in the oldest disguise there is. There is a running joke about which of them is better at the masquerade, and the episode lets it land gently.

The episode is a small reminder that the best undercover work is mostly patience, and that Bulman is better at waiting than he is at retiring.