But his mournful dignity when addressing the House conjures an almost classical sense of melancholy. He surveys the Labour benches like an ancient Roman contemplating the depredations of lead plumbing and high living. Sometimes he rages against the dereliction of the old ideal, but more often he admonishes his colleagues with a sorrowing and indefatigable gravity.
Yesterday provided the perfect arena for his skills in this mode, as he proposed a Bill designed to oblige the Government to seek endorsement from Parliament before embarking on any open-ended venture of international discipline.
Mr Dalyell wants to record a protest, and it's difficult to think of any human agency that could deflect him when he is so minded. "The first quality is not to mind being a bore," he has said about his weevil ability to tunnel into the dense hardwood of ministerial prevarication. Quite often, there is a muted groan when he stands to speak but there was nothing boring about his performance yesterday, which converted a distracted, desultory atmosphere in the House into one still with attention.
He first took the high ground of seniority, pointing out that those with first-hand experience of war and bombing might take a different view of it than those "inoculated against weapons of mass destruction by watching Indiana Jones".
And then he urged the Prime Minister to look to his theology books again. Mr Blair had "set out his stall as a Christian Socialist" he noted. Honest Tone might have all the big names but his Aquinas and Augustine didn't smell quite right to Mr Dalyell.
Most effectively, he presented this as a matter of parliamentary privilege rather than policy disagreement, the kind of approach, it seems, that can subdue all party enmities. Even Mrs Thatcher, he said, had sought the endorsement of Parliament before dispatching the task force to the Falklands. She might have sunk the Belgrano but she asked permission first. Here too, "the pros and cons should have been hammered out on the anvil of parliamentary opinion".
You could tell from the uncontested "Aye" that sounded after his speech that his had been a clean, well-aimed stroke.
A less distinguished demonstration of parliamentary rhetoric had been given earlier by James Clappison, who put a Private Notice Question about the release of sex offenders under curfew notices. Paul Boateng briskly cut down the kite he was flying by making clear that not one pervert would emerge from prison tomorrow. At this point Mr Clappison should have expressed his contentment and sat down, but a lot of work had gone into his supplementary question and he was loath to abandon it merely because it had been answered.
Mr Boateng, who usually bobs and nods like a novelty dog, became a freeze- frame of bemusement. Mr Clappison noticed his uncharacteristic paralysis and was unwisely encouraged by it.
"The minister's looking perplexed!" he said cockily, just before asking him to tell the House whether any sex offenders would be among those curfewed. Mr Boateng finally twitched into life to explain that he was only trying to work out why he had to give the same answer twice. "No!" He continued. "None! Not one! Not any! - I do hope the Honourable Gentleman has heard me."
"Thank you," gasped Madam Speaker, as though she had been surprised by this unequivocal full stop.