Sir Keir Starmer has urged Boris Johnson to "get on" with negotiating a Brexit deal so the UK can get back to fighting the coronavirus pandemic.
The Labour leader said the PM is "wrong" to propose changing a key Brexit agreement with the EU after a Cabinet minister admitted a planned move to row back on aspects of the Brexit Withdrawal Agreement would “break international law”.
The government will introduce the Internal Market Bill on Wednesday, which aims to ensure goods from Northern Ireland continue to have unfettered access to the UK market while making clear EU state aid rules – which will continue to apply in Northern Ireland – will not apply in the rest of the UK.
He criticised the plan to introduce new legislation over-riding elements of the Withdrawal Agreement and suggested Mr Johnson could be using the proposal as a distraction.
The Labour leader urged the government to "concentrate" on achieving a deal with the EU instead of "reopening old arguments" and said it would be a "failure" if a free trade agreement wasn't reached.
"Get on, negotiate, get the deal that was promised," Sir Keir told ITV News, adding: "If this ends up without a deal that will be a failure on the part of the government."
He insisted negotiators have enough time to iron out any outstanding issues and come to a deal before the PM's October 15 deadline.
He said the government needs to focus on winning a deal so it can get back to the more important issue of tackling coronavirus.
"What we need to do is focus on what's in the national interest, and what's in the national interest is getting a deal, the prime minister promised a he would get a deal, he needs to deliver on that promise.
"I don't think the issues that are outstanding can't be resolved, so let's get a deal, move on, and focus on what the public are concerned about which is defeating this pandemic."
He welcomed the PM's October deadline and said he would not seek to extend it, were he in Mr Johnson's position.
Sir Keir, who was previously a passionate Remain supporter, told Political Correspondent Paul Brand that he is not calling for a new EU referendum.
"I don't think there's any need to extend the trade talks, there's no talks of extending them," he said, adding: "We've left the EU, there's no question of a second referendum...the Leave/Remain argument is over."
The Labour leader, while criticising the government's response to the coronavirus pandemic, urged the public to follow all the advice.