William Rouche jacket on ITV?
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Just switched over to have a look. Impossible to tell the brand, I'd say. Looks like a fairly standard 2 button single-breasted navy blazer with 4 buttons on the sleeve. Pretty standard lapel width and shoulder padding. Buttons look fairly substantial/chunky, which is the way to go I think if you're going for metal buttons. Seems to fit quite well; he often wears stuff that fits decently.
Switching back to BBC2 now (good series on the Romans, presented by Mary Beard, is on).