Theresa May should give the Brexit vote similar respect to a poll in which people backed naming a ship Boaty McBoatface, the Commons has heard.
Labour’s Paul Flynn made the claim as he warned the Prime Minister her “little Englander” attitude risks splitting the UK.
Ministers have been clear the Leave vote at June’s EU referendum must be respected and implemented.
But Tory frontbencher Jo Johnson earlier this year vetoed a public vote in favour of calling a £200 million polar research ship Boaty McBoatface.
The comical name topped the poll with more than 124,000 votes - more than three times its nearest rival - but Mr Johnson instead chose RRS (Royal Research Ship) Sir David Attenborough.
A miniature, unmanned submarine on the vessel instead received the Boaty name.
Speaking in the Commons, Mr Flynn (Newport West) asked Mrs May: “Doesn’t the decision taken in the referendum deserve similar respect to the public majority in favour of the name Boaty McBoatface that was taken?
“Do you notice that there’s been a strong movement in public opinion in Wales against Brexit because people realise the promises made by the Brexiteers will not be honoured and they see the effects now on the Welsh economy?
“There’s going to be an awful result in Ireland to fixed, hard borders that will not be enforceable and will be hugely expensive.
“You’re ignoring the views of the people of Scotland.
“Don’t you think your little Englander myopia will lead to the break-up of the United Kingdom?”
Mrs May replied: “The United Kingdom voted to leave the European Union. This Government is putting that into practice.
“You and others can try all they like to reverse that decision, to try and delay the application of that decision, to find ways to weasel around that decision.
“The British people spoke, this Parliament said to the British people it is your choice. They chose, we will now do it.”
Mrs May, on the start of formal negotiations to leave the EU, said in response to a separate question from Tory MP Matt Warman (Boston and Skegness): “I think it’s important that people see we are committed to invoking Article 50 because there are those, I fear, who wish to delay the invocation of Article 50 as a proxy for not leaving the European Union.
“But it’s important that we do give people the certainty and that’s why I’ve set out that we will invoke Article 50 by the end of March next year.”