Political Correspondent, BBC West
Our Great Westerners campaign profiles the Somerset man who led Parliament in the civil war.
He is a local boy, and without him the King could have you arrested in the dead of night, and carted off to be executed.
It would be an impressive claim anywhere, but the man drumming up the Pym vote knew his audience would be particularly impressed.
Cllr Chris Clarke, and supporters, canvassing outside the school
The six lads around him were all Brymore school students, and Pym is their man.
He was born there in 1583, when the building was a private house.
Now the house has grown and Brymore is one of a handful of state boarding schools, sitting in the Somerset countryside just outside Cannington, near Bridgwater.
Famous old boy
Pym is their most famous old boy, and cuttings about him are pinned to the walls in the school corridors; every eagle-eyed schoolboy knows his name.
Chris Clarke, a senior Somerset county councillor, had come to the school with Bristol University's Professor Ronald Hutton.
They were trying to raise the vote for Pym in our Great Westerners campaign, and Brymore seemed a good husting ground.
At dinner time, Josh, Shaun, William and three other mates went canvassing.
Vote for John Pym
They hand out the Great Westerners cards proclaiming No Pym, No Parliament!
Other lads know the name, but need reminding why he's worth voting for.
"If it wasn't for him" says Josh, remembering the politician's words, "you could be arrested and just taken away".
"But because of Pym there is a Parliament and you get a trial in court."
Lots of nodding over the beef stew, and everyone round the table takes a card.
Charles the First, it is fair to say, hated John Pym.
Leader of the increasingly restless House of Commons, Pym challenged Charles' claim to be king by divine right.
"He is still the only MP to have a warrant for his arrest issued by the monarch" says Prof Hutton.
Pym faced arrest
Charles actually sent his men to Parliament to have him arrested.
Had he been, the civil war would not have started, and the whole history of these islands would have been different.
Charles sent his men to Parliament to have Pym arrested
As it was, the incident merely fuelled the republican cause. Parliament's army grew, and the civil war followed.
Pym, of course, was fighting as much for his puritan faith as the powers of Parliament as we now see them.
But even after the monarchy was restored, the principle that Parliament's will should prevail over the king's was established, and that, to this day, is the legacy of a man born in Cannington.
Ironically for Pym, Parliament today is not the vote winner it once was.
Chris Clarke even suggested we change No Pym, No Parliament to No Pym, No Freedom.
"That would win more votes", he suggested, "because our freedom from tyranny is the real legacy of John Pym."
So, if you value the right to elect MPs who can't be bossed about by a despotic monarch, then Pym's your man.
So far we've heard the case for two other Great Westerners: Alfred the Great and William Tyndale.
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