At least £2.1bn worth of old £10 notes need to be spent or exchanged before they cease to be legal tender, the Bank of England says. The deadline to spend or exchange old £10 notes - featuring naturalist Charles Darwin - is 1 March. Plastic polymer tenners depicting author Jane Austen entered circulation in September. Currently, weekly returns of paper £10s are averaging at a value of £85m or 8.5 million notes, according to the Bank. To exchange an old tenner, people can either post the notes to the Bank of England, or visit the Bank in person in the City of London. The Bank will exchange all old £10 notes indefinitely.

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