Political commentator John Mills has blasted Owen Smith over his pledge to stop Brexit.
Smith, who is fighting Jeremy Corbyn for the Labour leadership, has revealed he will attempt to block the government triggering Article 50 until there is a second referendum.
The MP for Pontypridd said: "The British people were lied to by the Leave campaign - they deserve to have a say on whatever exit deal the Tories strike with the EU.
"Under my leadership, Labour won't give the Tories a blank cheque. We will vote in Parliament to block any attempt to invoke Article 50 until Theresa May commits to a second referendum or a general election on whatever EU exit deal emerges at the end of the process."
But Mills, who is also the chair of Labour Leave, feels this is "very undemocratic."
"It [the EU referendum] was a decisive result and a democratic result," he told Jonny Gould and Ash. "I think Labour has got to accept this. This is very bad politics.
"There's no appetite among the elecorate at large to run a referendum again or have it all reversed through a general election campaign.
"It's completely wrong to go back over the ground again."