If a fair few of the 300,000 Britons who live in Spain woke with pounding heads on Saturday morning, many could at least console themselves with the thought that the nagging sense of regret they were feeling was probably not self-induced.

Some of those migrants who voted Remain held their own Brexit wakes. Those in the other camp, meanwhile, reached for the cava to toast their native country’s future from the warmth of an adopted shore.

Ian Hassell, a 55-year-old events promoter who has called Spain home for 20 years, went on a tapas crawl to try to ignore it all. “Yesterday I was really mad but today it feels like the last stage of grief: acceptance,” he said. “So now bring it on, eh? Let’s see them make a complete mess of it all.”

Hassell, who runs a Sunday drag-queen bingo brunch in Madrid’s LGBT quarter, says the uncertainty of recent months had affected the business but he hopes things will pick up now.

“I think, long-term, it will probably be okay because the Spanish government, ironically, are being much kinder to us British immigrants than the Brits. I think the market’s too big not to come to an agreement over tourist visas and mutual deals.”

We’ve got our health cover and freedom of movement – at least that uncertainty’s been taken away Les Buchanan

Hassell doesn’t miss his native Liverpool, nor, come to that, does he miss the UK – “I feel more European than British anyway,” he says.

Asked whether the remainers got it wrong and Brexit may yet yield unexpected benefits, Hassell doesn’t hesitate: “No. It’s going to be a shitshow.”

Les Buchanan, a 76-year-old Scot who worked as a diplomat for 40 years before retiring to Spain in 2000, was one of those who chose to mark the occasion. He and his wife, Louise, had some friends over to their home in Barcelona. The “little wake” broke up at 3.30am.

“It’s sad, isn’t it?” he says. “But, having left, this was almost the best outcome for us because the withdrawal agreement guarantees our rights. Future generations have been chucked under the bus, like the Irish. But we’ve got our health cover and freedom of movement. At least that uncertainty’s been taken away.”

If the uncertainty has gone, though, the regret has not. Buchanan is annoyed that Brussels’ best minds have been tied up with Brexit for years when they could have been looking at other issues, such as immigration, and the machinations of Donald Trump and Vladimir Putin. “It was such a waste of time and money and brains,” he says. “You just despair.”

Beneath the frustration lies a layer of deep sadness. “I just cannot understand these people who hate the EU. I can understand saying what’s wrong with it, but why would you hate this attempt to have 28 countries with God knows how many languages and 400 or 500 million people voluntarily giving up a little bit of their supremacy to create this vision?” he asks.

“Flawed it may be, but when I was born, they were all on top of each other with bayonets and tanks. It’s just sad that people can’t see that.”

Others felt the same. Berta Herrero, a Spanish journalist specialising in the EU, watched all her British friends retreat to the bar on Friday night. Her own breaking point came on Wednesday when MEPs sang Auld Lang Syne in the European parliament chamber. “Afterwards, I was on the sofa, basically crying my heart out,” she said. “And yesterday, it was just the comedown and, ‘It’s done’.”

But, tears aside, Herrero points out that Brexit is already leaving its mark on the politics of one of the most traditionally pro-EU nations on the continent. The UK’s departure was noted by both Catalan separatists and those on the far right.

“In Spain, we’re meant to be united against what the British government is doing, but there were some voices who were saying, ‘Even if it’s super-sad, I don’t share this sadness because they’re doing the right thing; they’re going to be free of the Franco-German whatever, and they’re going to do so well’.

“But when you look at those voices, it’s the pro-independence people from Catalonia and people who are on the right and the far-right. It’s weird because if you’d asked me four or five years ago, 99% of Spaniards would have been like, ‘No, they’re going to be worse off and it’s so sad.’”

Midnight’s momentous change went unmarked in the James Joyce pub in central Madrid, a haunt of expats, tourists and the odd local. As the covers band played Folsom Prison Blues, Superstition and I Still Haven’t Found What I’m Looking For, Lyn Sexton, a retired NHS worker from Wales, was reflecting on Brexit.

“I’m not really feeling emotional but I’ve always only known the UK to be part of the EU,” he says. “I’m a little bit worried that we don’t have the industry. I just hope we can sustain ourselves and prove ourselves.”

The Observer couldn’t help but wonder how he’d managed to retire in his 40s. “I won £1m,” he says. “On the EuroMillions.”