His loud, very loud, sweary rants are full of righteous indignation over a disUnited Kingdom that, in his opinion, has become a toxic skip fire fuelled by exceptionalism, warped English nationalism and the class system.
On Saturday night his targets for expletive-strewn ire included Shrewsbury's MP and several prominent Tories but also Labour leader Keir Starmer, field sports enthusiasts, golfers and most especially the Prime Minister, variously described as a "clown" and "the Cookie Monster went to Eton" at the very mildest end of the insult spectrum.
The veteran comic's two-hour show had a rambling, free form feel with no tangents unexplored, as he bounced off answers from a reticent audience in Theatre Severn's studio theatre. Some of that reticence was probably due to the forensic way he would deal with hecklers, honed from 36 years as a stand-up.
Between the diatribes he talked about his diabetes diagnosis, revealed his love of music hall (even breaking into song) and of his cantankerous South London mother, who insists on him buying her the Daily Mail (Mail, Comrade? says the newsagent).
He was also full of admiration for Shrewsbury Town's victory that afternoon over MK Dons, a club uniquely loathsome to an AFC Wimbledon fan like Mark Thomas.
The second half of his 50 Things About Us show, based on his book about surprising statistics and historical facts about Britain, revealed some jaw-dropping information. This includes that compensation paid to slave owning aristocrats after abolition led to a debt only finally paid off by taxpayers in 2015. Or that more land in this country is dedicated to grouse moors than housing.
Apart perhaps from a small group of people who abruptly departed, Thomas was preaching to the converted (he asked if the gig doubled up as the Shrewsbury Socialists' meeting) but there was no doubting his passion.
His tour continues with shows at Wolverhampton's Newhampton Arts Centre on November 13 and Birmingham MAC on November 24 and 25.