The Bank of England has also announced that the £20 note will follow the £5 and £10 in switching to polymer, and a competitive tender for the supply of the polymer substrate for the new £20 should be underway by the end of the year.

Addressing this week’s Follow the Cash conference at the University of the West of England in Bristol, Bank of England chief cashier and director of notes Victoria Cleland, said: “We have made good progress in designing the new notes, and our printing partner De La Rue will start mass producing the new £5 this month on the polymer supplied by Innovia Films.”

The Bank is planning a phased introduction of the new-style banknotes, and is working closely with the cash industry and cash supply chain via a number of working groups.

Training materials for banks and retail staff, along with a public information campaign, will precede issuance.

The polymer £5 is set to go into circulation in the autumn of next year, the £10 will follow a year later in 2017, with the £20 “expected to launch in the next three-to-five years”.

That leaves just one remaining paper note, the £50, which is not in such widespread circulation as the other denominations. A Bank of England spokeswoman said no decision had been taken yet regarding the £50, and any new issuance was likely to be “quite a way off”.

There are some 3.2bn Bank of England banknotes currently in circulation, with a total value of more than £60bn. The £20 is by far the most widely-used, with more than 1.9bn in circulation, followed by the £10 (737m notes), £5 (320m) and £50 (236m).

Cleland said the polymer notes would deliver “a leap forward in counterfeit resilience” thanks to sophisticated security features and the ability to include complex windows in the design.

The Bank removed 430,000 counterfeit notes from the cash cycle last year.

The process of deciding on the next character to be featured on the upcoming redesign of the £20 is also well underway. Members of the public were invited to nominate visual artists “who have helped shape British thought, innovation, leadership, values and society” for consideration.

William Caxton, the first English printer; typographer Stanley Morison, the creator of Times New Roman; and letter cutter David Kindersley appear on the longlist of nominees, which will now be whittled down to a shortlist of three-to-five names ahead of a final decision next spring.

Sir Winston Churchill will be on the new £5 note, and Jane Austen will feature on the upcoming £10 design.