Yet despite such factors, Sir Keir may quickly find the ghost of Europe coming back to haunt his government like it has with others. While Leave voters have mostly moved on, many of those who voted Remain still begrudge the result, McDonnell says.

The latest voting intention numbers suggest most Remain voters plan on backing Starmer at the election.

“Labour voters are overwhelmingly in favour of rejoining the EU. If we ask the question in isolation, 80pc of Labour voters would vote to rejoin,” he says.

If elected, “there will be a lot of pressure from backbench MPs and other campaign groups to go further” in strengthening the ties than the party has suggested it plans to, says Henig.

Just as the Conservatives in favour of a hard Brexit formed the European Research Group (ERG), he suggests hardline Remainers may form a “reverse” ERG faction in Labour.

“Something like that can definitely be expected,” Henig says.

Another push for closer ties will come from business groups, who are warning their members are being held back by trade restrictions.  

The British Chambers of Commerce has made improving “EU relations to cut costs for businesses” one of their key election lobbying points.

William Bain, head of trade policy, said the group was pushing for “close alignment on regulations that impact Britain’s global trade, such as standards on manufactured goods”.

He said: “The Government should only diverge from EU rules where it adds value to UK plc.”

The Confederation of British Industry is also lobbying for closer relations. Sean McGuire, Europe and international director, said: “Our members don’t want politics winning out over economic common sense. They want to see both sides working in the spirit of openness, collaboration and compromise.”

Henig says the best Britain can hope for is a “patchwork” of small agreements.

“There will be lots of talk but there’ll be a lot of reluctance to go too far, too fast. There is a lot of caution on both sides about making too many big changes,” he says.

Ultimately, “nothing will make a big difference on growth. We’re not going to rejoin the EU anytime soon”, he says.

If Labour wins power the relationship between London and Brussels may become more civil, but “in practical terms I don’t think [it] will change very much”, Menon says.