• e-mail

Cash users are being urged to dig deep into their pockets in search of old £50 notes as the currency will no longer be legal tender next year. 

The Bank of England launched a new plastic £50 banknote last week featuring an image of Second World War codebreaker Alan Turing. 

It is replacing cotton-paper notes containing images of scientist James Watt and entrepreneur Matthew Boulton. 

Extra security: The Bank of England launched a new plastic £50 banknote featuring an image of Second World War codebreaker Alan Turing

The older £50 notes are being phased out and will not be accepted in shops from the beginning of October next year. The new polymer-printed £50 is harder to copy for fraudsters and also more durable – so it should not get damaged if accidentally put into the washing machine. 

It is also hoped the latest rose-tinted notes will be more acceptable for shopkeepers who often baulk when people try to hand over big notes for fear that they could be forgeries. 

The new currency includes added security measures that include a 'fifty pounds' hologram, transparent windows and a metallic image of the Queen. 

This is on top of the metallic thread and the colourful patterns visible under ultra violet light that are features of existing £50 notes. 

Despite not being able to spend the old notes after September 30 next year, they will not become worthless. 

You should still be able to exchange notes at your local bank or at a major post office. 

Alternatively, it is possible to exchange expired notes directly with the Bank of England – either in person or by post. 

Details and forms can be downloaded at bankofengland.co.uk. Copies of photo ID (for example, a driving licence), plus proof of address (such as a bank statement) must be included. 

A Bank of England spokesperson says: 'This £50 note is our most secure banknote yet.

'One in five people still choose cash as their preferred payment method – and we will continue to cater for this demand. The simplest way to exchange old notes is to deposit them with your bank.' 

There are currently 375million banknotes for £50 in circulation – up from 221million in 2014. 

This is despite the use of cash on the high street falling in recent years. Old £20 banknotes with the image of economist Adam Smith are also being phased out and will also not be legal tender from October next year. The new polymer £20 note, featuring an image of artist JMW Turner, was issued in March this year.