London-Members of the Driscoll family tend not to fight. If they do, it’s over whose turn it is to vacuum.

Leslie Driscoll, 55, sells hot cross buns in an English bakery in London and addresses her customers with “love” or “darling”; her husband, Peter, 54, works as a floor layer; their daughter, Louise, a 19-year-old with dyed blue hair, is a barista in a hip coffee shop.

However, last week, the Driscolls fell out; badly.

They had an argument so big they did not speak to one another for days, Ms. Driscoll said.

Shortly afterward, her husband went off in a huff to see friends up north, in Derby.

The source of the family drama: whether Britain should exit the European Union, a process often referred to as “Brexit.”

With only days to go until the referendum on membership in the bloc on Thursday, polls suggest that the country is deeply split along socioeconomic and regional lines, with many older and working-class voters in England favoring leaving, and younger and better-educated Britons, and a majority of those in Scotland and Northern Ireland, favoring staying.

As the consequences of the choice come into focus for voters, tensions are bubbling.

In the case of the Driscoll family, they are boiling over.

“I completely disagree with her,” Louise said on a recent afternoon, looking her mother squarely in the face as they sat in a cafe.

“We shouldn’t be leaving, like, an organization that has helped us more than we could ever help ourselves if we were to go it alone.”

Louise is the only one in her family who wants Britain to remain. Her parents and her 80-year-old grandfather want out.

“This is a little island,” her mother said matter-of-factly, lighting up a cigarette and letting the ash fall on her glittery sneakers.

“We should look after our own first. Charity begins at home.”

“But we are all people!” Louise said. “We should help each other.”

“It doesn’t work that way, darling,” her mother replied, shaking her head.

“If you’re born here, you pass as English. I don’t care whether you’re black, white, green or blue, or purple with pink spots on — you’re English.”

Those born abroad, Ms. Driscoll said, “have got their own governments, their own parliaments, whatever.”

Up and down the country, the debate is pitting husband against wife, children against parents, and sisters against brothers. The divisions are unlikely to heal easily after the referendum is decided.

Even the family of Boris Johnson, the former mayor of London and the most prominent face of the campaign for leaving the bloc, has not been immune to disputes: His father, Stanley; sister, Rachel; and brother, Jo, who is a member of Parliament and who worked closely with Prime Minister David Cameron, favor remaining in the union.

Boris Johnson’s mother, Charlotte Johnson Wahl, wants to leave. (Rachel Johnson reportedly tried, without success, to dissuade the former mayor from backing a British exit over a soggy game of tennis.)

In Islington, the neighborhood in London where members of the Driscoll family have lived for eight generations, residents are increasingly going public with their voting intentions, which is a rarity in Britain.

Rows of houses on some streets have “Remain” posters in their windows.

On a thoroughfare filled with butchers, bakeries and fish-and-chip-shops, tradespeople nodded their head vigorously when asked if they were planning to vote out.

The clash over Britain’s continued membership in Europe has touched on issues as varied as immigration, terrorism, the economy, London’s housing shortage and the fate of the National Health Service.

Some of these issues, like immigration, are directly related to the European Union.

Others, like the shortage of affordable housing, have little to do with it.

Yet, those distinctions are blurring. For many, the referendum is as much a chance to register displeasure with the country’s direction as it is an opportunity to reject or embrace Europe.

The stance of some voters is being shaped by personal experience and anecdote.

There is, for example, a widespread perception that European citizens are flocking to Britain, especially from Eastern Europe, to take advantage of its social welfare system.

Nevertheless, Britain’s welfare system is not as generous as those of many other European nations, and fewer than 7 percent of immigrants receive benefits.

In Ms. Driscoll’s case, she remembers her grandfather pawning and re-pawning his suit to get by.

That memory was revived, she said, with the discovery a few years ago that a newly arrived Polish family in her neighborhood had received money to buy a car and move into a four-bedroom house.

“Years ago, we never had social security or anything like that,” Ms. Driscoll said. “You sold your own.”