A summary of Labour's state of play from the Observer, backed up with the results of a survey:

Labour supporters press Corbyn on EU
Majority back Britain staying in single market and customs union
by Toby Helm and Michael Savage

Jeremy Corbyn is under huge pressure to shift party policy on Brexit as an exclusive poll for the Observer reveals a substantial majority of existing and potential Labour voters want him to back permanent membership of the EU's single market and customs union.

Four times as many Labour supporters favour that option as oppose it. The survey by Opinium also finds that more than twice as many in this group want Corbyn to support a second referendum on the eventual Brexit deal as reject it.

The poll comes at a time when senior European politicians are signalling that Britain could reverse its decision to leave the EU and warning that there will be no prospect of reaping the benefits of membership from outside the bloc.

Emmanuel Macron will say today on The Andrew Marr Show that he would love to see Britain return, adding: "It depends on you. I do respect this vote, I do regret this vote, and I would love to welcome you again." However, he warns that full access to the single market for the UK's huge financial services industry will be "not feasible".

The CBI is preparing this week to call on the government to abandon the pursuit of global trade deals in favour of long-term EU customs union membership. In the wake of the Observer poll, senior Labour MPs are saying it is no longer credible for a party that is serious about power to overlook the demands of so many trade unions, supporters and business leaders.

The former shadow business secretary, Labour MP Chuka Umunna, said: "It is absolutely vital, as the party of work and social justice, that we have a clear and unequivocal policy to keep the UK in the single market and the customs union.

"When our members, our trade unions, our businesses, Labour voters and potential voters are all giving the Labour party the same clear message that this is what the country needs, it does not make any sense at all to ignore it."

Opinium found that among all potential Labour voters at the next election, 56% want the party to back permanent membership of the single market and customs union, while just 13% think it should remain opposed; 30% had no firm view either way.

Among younger voters, the balance in favour was even clearer: 63% of all "young professionals" who are potential Labour backers were in favour, against 10% who were opposed. Of the "young blue collar workers" who might back Corbyn's party, 61% were in favour of the change against just 4% who were against.

Significantly, even among Labour voters who backed Leave, 37% said they want Corbyn to support permanent single market and customs union membership compared with just 26% who did not.

Some 51% of Labour's potential pool of support backs a second referendum on the final Brexit deal, against 23% who oppose the idea.

Despite mounting disquiet among pro-Remain Labour MPs, Corbyn has so far rejected calls to back staying in the single market and customs union. Labour's current policy is to keep the UK in both only for the duration of a post-Brexit transition of up to four years. After that it would try to negotiate a relationship offering the "exact same benefits" for the UK post-Brexit. Corbyn has also refused to endorse a second referendum.

There's too much strain in Labour at the moment, with the vast majority of supporters not in line with the party leadership. Something's got to change, and I think it will. God knows what Jeremy is waiting for.