By Alex Fraser and Georgina Cooper

LONDON (Reuters) - When the pound plunged this month on new worries about Brexit, New Yorkers Derek Hotter and Ian Clark hopped on a plane for an impromptu holiday in Britain.

Record numbers of dollar-, yuan- and euro-rich tourists eager to snatch a bargain could be a silver lining after the sharp decline in sterling since Britain voted to leave the European Union on June 23.

The vote took many investors and chief executives by surprise, triggering the deepest political and financial turmoil in Britain since World War Two and the biggest ever one-day fall in sterling against the dollar.

The pound has fallen 28 cents since the night of the vote, dropping to $1.2215 <GBP=D4> on Tuesday.

Britain saw tourist numbers rise in July, with visits up 2 percent from the same month last year to 3.8 million.

"We've done a bunch of shopping," Hotter, who is in digital marketing, told Reuters in London's Piccadilly Circus.

"I was here a couple of years ago and it was a little harder spending and now you come over here knowing it's so much better in our favor, you feel like you can shop a little bit more."

Americans last year spent 3 billion pounds in Britain, making them the most important tourists for the United Kingdom.

"In a period post-referendum, post-Brexit this is the shining star industry that is benefiting from, amongst other things, a weakening of the pound," said Christopher Rodrigues, chairman of the British Tourism Authority.

He said the weak pound is an attraction for Chinese visitors, but the marketing focus for pulling in more of China's 100 million who travel overseas is more long term.

    "We need to keep going at that market because the real tidal wave of Chinese visitors is going to be probably five to ten years from now when the market has got a lot bigger," he said.

    Bookings from China to Britain are up by nearly 25 percent between now and Christmas, with the lure of London's luxury quarter attracting many.

"Exchange rate you know, it's lower than before," said one Chinese woman explaining why her mother chose this month to visit.

    "Many discounts here. Especially for Chinese customers I think," said another excited shopper.

    Even though continental European visitors do shorter stays and spend less money than their American counterparts, they are important. Visit Britain predicts a rush of European visitors in the coming months.

    "I think we are going to have a real crush in the sales this Christmas, because I think there are going to be a lot of Europeans here and Brits will have to get their trainers on to get ahead of the line - but that's great news for us," said Rodrigues.

(Writing by Guy Faulconbridge; Editing by Janet Lawrence)