Walking through town all you'll see are smiling British faces and hear people speaking proper local English. That multiracial gang of hoodies that hung around the park will have been replaced by a bunch of public schoolboys playing cricket and shouting things like "Jolly good show!", the girls drinking cider by the bus stop will now be tucking into ham sandwiches and scotch eggs with lashing of ginger beer. What was previously Salim's Kebab Palace will now be a proper English chippy, everything comes with extra gravy and a piece of haddock will cost less than a quid as the removal of fishing quotas will have made all forms of fish bountiful and completely sustainable. What used to be a chicken shop is now a proper English pub, with real ale that isn't interfered with by the EU, you'll also be able to smoke indoors like a real man. Outside streets will be clean and pothole free, all the lawns freshly cut, all the cars new and shiny (in part thanks to the amazing trade deals Germany had to give us when they realised they needed us to buy their cars). People will leave their front doors unlocked and children will play safely in the street again, without fear of traffic or strangers.
On the rare occasion you do see a foreigner, if it's not a tourist partaking of our thriving competitive tourism sector come to wonder at our green and pleasant land, it'll only be some humble national stereotype, eternally grateful for the opportunity to dwell in our utopian nation. You might run into Deepak, the only Indian in town, turbaned and dressed in the traditional garb of his people, loyal servant of the British Empire who is entrusted to work as a hotel doorman. Perhaps you'll meet Gorge, a swarthy Spaniard prone to afternoon naps with a comical demeanour who is permitted to work as a waiter, or Antoine his maitre d, a suave sophisticated Frenchman with a thin moustache and a slight odour of garlic, perhaps you'll even meet Svetlana, an absurdly beautiful sultry Swedish exchange student who finds it impossible to resist the charms of a true moderately overweight middle aged Brit.
As you can see there's no reason to think that post-Brexit Britain won't be a shining beacon of progressive cultural diversity for the world, it'll simply be that all the immigrants will be "good immigrants", the kind that speak perfect English, act just like Britons and earn over £36,000 a year, paying half of that to the government for the privilege of using the NHS. The NHS now of course being a luxury service with private rooms for every patient each fitted with a state of the art 4k resolution 3d television and a new gaming console.
From then on things will only get better. The EU will collapse and be so poor they'll accept anything we offer, world investment will flood to Britain, countries will sign agreements allowing Britons freedom of movement all over Europe so you can still retire in Spain, but won't expect us to return the favour. Good old British industries like car manufacturing and coal mining will become world leaders. Jobs will pay so well that the whole country will be living like kings, the pound will be worth so much we'll be able to go on holiday and it'll be cheap like it was in the old days.
Britain will go from strength to strength. Canada, Australia, India, they'll all decide to get the old team back together and willingly take dominion status, thus making Britain the greatest super power in the world. It will be a British renaissance, the BBC will make comedy even funnier than the time Del Boy fell through the bar, and drama even more intense than the Great British Bake Off. Brexit is going to be a dream, don't you worry about it.
From https://m.reddit.com/r/unitedkingdom/comments/58v4hv/brexit_leading_banks_set_to_pull_out_of_uk_early/ - which has a load of other fantastic responses to the banks deciding that Brexit Britain is not a good base...
Original post on Dreamwidth - there are comments there.