I was in a small shop in London last month and the sales clerk refused to accept my Visa after noticing the lack of chip. The explanation was that the company's insurance company would not cover them for fraudulent card use for non-chip cards. It was not related to the difference between debit and credit cards. This is the only trouble I've had in hundreds of transactions although many vendors do first try to enter my card into their chip reader.

The continued increase in credit card fraud was a topic of a special report in the news that week, so there could be a corresponding increase in the difficulty using non-chip cards.

Thanks for asking this question. I was planning to try to get a chip card for future travel but it sounds as if the question has been answered here.