Good Morning Britain
"Next time I promise to spend at least five minutes on Thunderbirds."
The general secretary of the rail union appeared on the ITV breakfast show to discuss the strikes of railway workers this week.
The former BBC Breakfast host spoke out about incident in which he felt his daytime rival crossed a line.
Guest Quentin Letts clashed with the presenter over the UK's treatment of refugees, saying: "There's no point talking to you."
"Mr Raab, with respect, I know what you’re going to say."
As you'd expect, Piers has already fired back on Twitter.
Richard Madeley Clashed With Labour MP On GMB
Labour MP Shares Bleak Assessment Of What Has Happened To UK In Boris Johnson's Hands On Question Time
"Our country deserves better and we will not get better until Boris Johnson is gone," Peter Kyle said.
Just shy of 100 people complained to the TV watchdog after Johnson's recent interview on Good Morning Britain.
The prime minister threw an unintentional bit of shade her way earlier this week during an interview with Susanna Reid on Good Morning Britain.