Martin

Martin is Jonny's younger brother in this scrappy family sitcom, a small, watchful presence who gets swept along in whatever scheme or scrape his sibling has cooked up. He's more mischievous than malicious, quick to needle Jonny and just as quick to run for cover when the trouble he's stirred actually lands.

The part works because it doesn't try to be more than a kid brother: the writing gives Martin just enough cunning to make him a genuine irritant rather than a prop, and Dexter Lynch plays him with an unbothered, needling calm that makes his teasing land harder than shouting ever could.