The next £20 banknote will be printed on plastic in moves to help keep cash "fit for purpose", the Bank of England has announced.

The new note will be made from polymer, which is a more durable, secure and cleaner material than paper notes, and it will enter circulation in three to five years' time, the Bank said.

The move follows an announcement in 2013 by the Bank that the next £5 and £10 banknotes would be printed on polymer.

The £20 note is the most common banknote in circulation, with 1.9 billion in circulation at the end of February, according to the Bank's website.

The polymer £5 note featuring Winston Churchill will be issued in autumn 2016, the £10 polymer note featuring Jane Austen entering circulation a year later.

The move to plastic notes will leave the £50 as the only remaining paper note. A decision on whether to print the £50 on polymer will be made in due course.

Victoria Cleland, the Bank of England's chief c ashier, told a conference in Bristol how the next £20 note would be printed on polymer.

In a speech to the Follow the Cash Conference, she said that while technology had significantly changed the nature of payments in the UK, "cash remains a vital part of the mix".

She said: "Polymer - incorporating complex windows and sophisticated security features - delivers a leap forward in counterfeit resilience."

She said: "Cash is not ready for the retirement home, and certainly not the funeral home.

"And because there is a lot of life left in cash, we need to keep it healthy and fit for purpose."

The new £20 note will feature a yet-to-be-announced visual artist who has been nominated by the public.

Nominations closed in the summer, after people were asked to put forward the names of artists from fields such as architecture, fashion, film-making, photography and sculpture who have helped to shape British thought, innovation, leadership, values and society.

The character chosen will be announced in spring 2016.

A competitive tender process for the supply of the polymer for the £20 note is expected to start in late 2015, the Bank said.

Polymer notes are made from a thin, flexible plastic film, and like paper notes, they can be folded.

They tend to last at least two-and-a-half times longer than paper banknotes and they are resistant to dirt and moisture, so stay cleaner.

They also have advanced security features, making them difficult to counterfeit, according to the Bank.

Brand new polymer notes can sometimes stick together, and feel slippery, but these effects decline when the notes start to be used.

They tend to be slightly smaller than current paper notes.

Many countries already issue polymer notes, including Australia, Singapore and Canada.

Polymer banknotes entered circulation in Scotland in March, when Clydesdale Bank issued two million of the notes to commemorate the 125th anniversary of the opening of the Forth Bridge.