Rival speeches by the party leaders suggest the real debate is about whether to offer the EU the carrot or the stick

Labour and the Conservatives agree on one thing about Brexit: it will be fine as long as they are the ones elected. But behind their shared optimism about Britain’s ability to cling to the benefits of the single market without membership, increasing daylight is emerging between them on the best way of reaching this ambitious goal.

Jeremy Corbyn put a little more flesh on the bones of Labour’s strategy on Thursday in what was billed as a major policy speech in the leave-voting heartlands of Basildon.

Like the shadow Brexit secretary, Keir Starmer, before him, the Labour leader promised a more consensual approach, though gave few clues about what compromises he would be prepared to offer the EU. Crucially, there was no answer to the controversial question of how much immigration Labour might tolerate in its effort to preserve market access.

Yet in making clearer what it won’t do in power, Labour is at least setting a starker comparison with Theresa May, who spelled out a more sharply delineated version of her own strategy in a rival speech two hours earlier on Teesside.

Facebook Twitter Pinterest Theresa May campaigning in Guisborough. Photograph: Chris J Ratcliffe/Pool/EPA

The big difference between them is whether it makes sense to threaten to walk away from Brexit negotiations if EU demands become too onerous.

Labour says this is absurd. “Crashing out would the worst possible outcome,” said Corbyn. “There is no such thing as no deal. No deal is in fact a bad deal; it is the worst of all deals.”

May, on the other hand, is doubling down on her claim that only an enthusiastic embrace of the alternative “no-deal” scenario will help convince EU negotiators that Britain is serious about leaving and encourage it to make the necessary compromises instead.

“This great national moment needs a great national effort in which we pull together with a unity of purpose,” she said. “You can only deliver Brexit if you believe in Brexit. You can only deliver for Britain if you believe in Britain,” added the former remain supporter who now argues it is borderline unpatriotic to question whether no deal is in fact a plausible option.

There are other stylistic differences between them too, such as whether it makes sense to offer rights to EU citizens in the UK before reciprocal rights for UK citizens in Europe are agreed. But this is largely a matter of timing.

The real debate is about whether the EU is more likely to respond to the carrot or the stick: between what Corbyn calls the “posturing and pumped-up animosity” of the Tory position and what May calls his willingness to cave in to European demands “at any cost”.

We already largely know what the Tory stick looks like. No deal would introduce substantial new barriers to trade. The only question is whether the stick will be used to beat British business over the head rather than scare Europeans.

But Labour’s carrot is now taking shape too. In the TV debate on Wednesday, Corbyn hinted at migration being limited to the majority of workers who were coming to Britain with an existing job offer. In the Basildon speech he added a “crackdown on unscrupulous employers” and tackling domestic skills shortages as another way of limiting “exploitative” migration. Some fringe Labour figures such as the former Europe minister Denis MacShane argue these approaches could even be compatible with maintaining single market membership. Either way, Starmer claims migration will still come down under a Labour government.

Whether this more controlled version of free movement is enough of a carrot to persuade the EU to give Britain the market access it wants, or whether the Tory “big stick” approach will work best, we may never know – because only one of them will lead negotiations. What Britain should do if neither tactic works is a question neither main party is yet willing to put before the British electorate.