BBC viewers watched on as the pair began their day in Aberdeen before travelling through Cullen and on to auction at Elgin in Moray, but not before a brutal disagreement.
Catherine branded her fellow star “horrid” after he blasted her finds, saying she should be ashamed.
On showing him what she’d picked up, the 52-year-old slammed: “I don’t know what to say… so you bought a load of model railway books, you bought a pen… I didn’t like it. And, a reproduction fan.
“For £172 you should be ashamed of yourself. For that amount of money you could have done so well.”
Antiques Road Trip took a nasty turn today
Antiques Road Trip: Mark Stacey was pushed by Catherine Southon Antiques Roadshow's most valuable finds Sat, April 23, 2016
The Antiques Roadshow made their first million pound discovery in 2008, here are their most valuable finds to date.
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Antiques Roadshow presenter Fiona Bruce
I don’t think that was very nice at all
Clearly shocked by his remarks, Catherine was seen jokingly pushing him away from her and, when he tried to hug her, she told him: “Get your hands off!”
They both later addressed their argument solo and direct to the camera, with her looking hurt as she asked: “Wasn’t he horrid?
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“I don’t think that was very nice at all. He wasn’t complimentary about any of my items. He said, ‘He thought I should be ashamed of myself’, which was a bit of a cutting remark.”
Antiques Road Trip: Mark Stacey said Catherine Southon should be ashamed of her finds
Antiques Road Trip: Catherine Southon looked upset
Mark seemed far from apologetic: “I think she’s a bit made at me because I wasn’t overly enthusiastic about some of the items she bought. But, I’m not sorry.”
Despite not being remotely impressed, it was Catherine who sailed into the lead after their finds went to auction.
Antiques Road Trip continues tomorrow at 5.15pm on BBC Two.