Thomas Cook has suspended its online currency sales after unprecedented demand overnight, as the referendum results came in.
Throughout the night the travel company had been offering euros to click and collect at yesterday's favourable rate of €1.27 to the pound, despite the plunge in the value of the pound in the wholesale foreign exchange market.
Their rate has been cut to €1.21 today.
A rush of demand from holidaymakers trying to protect themselves against the fall led to queues snaking outside the doors at some Thomas Cook outlets this morning.
So the company suspended the online service to make sure that its counters did not run out of cash.
A Thomas Cook spokesperson said:
"We have temporarily suspended our travel money website following unprecedented customer demand for foreign currency overnight and this morning. We apologise to all customers affected. Our immediate priority is to ensure that we have enough currency in store to fulfil outstanding orders. We hope to be back up and running as soon as possible."