Britons on holiday abroad have overspent to the tune of roughly £500m this summer due to the fall in the value of sterling.
Recent retail sales figures from the Office of National Statistics (ONS) showed Britons spent more than expected after the EU referendum - but retail strategist Richard Hyman said "when the suntan starts to fade, they will start to tighten their belt."
Britons abroad will have spent 10-15 per cent more on eating out and visiting hilltop castles during the summer months due to sterling's post-Brexit slide.
Using government figures for tourism spend, Hyman calculated that the nation has spent £500m more on holiday in July, August and September due to the Brexit vote.
The overspend will be the Brexit vote's "first direct impact on consumers", Hyman said; when families return home, they will realise how the overspend has hit their finances, and reduce their outgoings.
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Retailers will also have to content with goods becoming more expensive next year.
"There will be a some direct impact of Brexit coming through in the next few months - but when the currency hedging runs out, things will become more difficult as the product becomes more expensive," Hyman said. "Its not clear to what extent retailers can pass that on to customers."
Shoppers have become used to steep discounts - and are happy to wait until a sale comes along. Online, retail giants such as Amazon lead the way, offering deals that other outlets are forced to emulate.