British Prime Minister Andy Burnham has reopened the debate over Britain's relationship with the European Union (EU), putting eventual membership among the options.

His remarks challenge Labour's previous red lines and raise a central question: how far is Britain prepared to go in rebuilding ties with the bloc?

In his first Labour Party conference speech as prime minister on Tuesday, Burnham said "Brexit has done more harm than good," and laid out options for "Britain's long-term relationship with our European partners."

In an interview broadcast by the BBC the next day, he said rejoining the EU was one option. "I would like to see Britain rejoin in my lifetime," he said, but added that he would "look at the different options."

Those options range from maintaining the current relationship to joining a customs union, participating in the single market or returning to full EU membership. They involve different degrees of economic integration and political commitment.

The openness to reconsidering those options contrasts with Labour's 2024 election manifesto, which ruled out returning to the single market or customs union and restoring freedom of movement. Burnham had also previously pledged not to reopen "divisive arguments about rejoining the EU," according to the Financial Times.

The debate comes a decade after 52 percent of voters backed leaving the EU in the June 2016 referendum. Britain formally left in 2020.

ECONOMIC CASE, POLITICAL RISKS

Burnham has made economic growth a critical argument for reconsidering Britain's relationship with the EU.

"I think we have seen growth harmed by Brexit and it's hard to see how we can get back to the higher levels of growth we once had by staying too distant from our largest market," he said in an interview broadcast by ITV News on Wednesday.

Polling also points to public support for closer ties, although that does not necessarily amount to a mandate for full membership.

A Public First poll found that 70 percent of British voters wanted the government to build a closer relationship with the EU, the Independent reported Wednesday. YouGov data published on the same day showed 59 percent support for rejoining the EU.

Reopening the debate also carries political risks. Labour MP Graham Stringer said it would be a "betrayal" for Britain to go back on the vote, and warned that the debate could be "more acrimonious" than in 2016.

WELCOME SIGNALS, BUT NO EASY RETURN

French President Emmanuel Macron and Spanish Prime Minister Pedro Sanchez welcomed the prospect of Britain's return. Macron said in English, "welcome back," describing a possible British return to the EU as great news for Britain and Europe.

Sanchez said Brexit had been a "huge loss" for both the British people and the EU.

Those responses signal political goodwill, but they do not establish agreement across the bloc on the conditions for British membership.

Rejoining would require negotiations over membership terms, the European Parliament's consent, unanimous approval by the Council of the EU and ratification of an accession treaty by Britain and all EU member states. Support from individual European leaders would be only part of that process.

A forthcoming UK-EU summit could provide an early indication of how Burnham intends to translate his remarks into policy. The summit originally scheduled for July was postponed and could be held in November. British media have suggested that Burnham wants it also to address the broader framework of UK-EU relations.

The immediate test is whether the government sets out a concrete negotiating position. That would help clarify whether Burnham is pursuing closer practical cooperation or preparing for a more fundamental change in Britain's relationship with the EU.