Britain’s New 5-Pound Note Is Chewable, Washable and Harder

It can withstand a spin cycle in a washing machine filled with extremely hot water. It can be eaten by mischievous toddlers or pet hamsters without causing lethal indigestion. It can fend off wily criminals with tiny lettering visible only under a microscope.

Printed for more than a hundred years on cotton paper, the 5-pound note now comes in polymer, a thin, flexible plastic film that makes it stronger, safer and more resistant to counterfeiters. The British central bank introduced the new bill on Tuesday.

The polymer notes, featuring the former Prime Minister Winston Churchill, went through rigorous testing.

To help fend off counterfeiters, the central bank added special new features. A silver foil patch at the bottom of Big Ben on the note has a hologram of the word “Five” that changes to the word “Pounds.”

Bank notes are important symbols of national identity. And the decision three years ago to replace the social reformer Elizabeth Fry with Churchill spurred some loud protests, since the queen would be left as the only female figure on British currency.

On Tuesday, Mr. Carney extolled Churchill as “one of the greatest statesmen of all time.” When Mr. Carney’s predecessor, Sir Mervyn King, first announced plans for the new Churchill note three years ago, he said that the new ?5 notes could be eventually referred to as “Winstons” and said it was appropriate that Churchill should be on “what is probably our most popular note.” Churchill’s words — “I have nothing to offer but blood, toil, tears and sweat” — appear on the bill.

The Bank of England has featured leading British luminaries on its notes for more than four decades, but a crucial criterion is being dead.