The banknotes of the future could be made from plastic rather than paper, under plans launched by the Bank of England.

If a public consultation reveals support, it will lead to the £5 and £10 note being transformed into a polymer plastic by 2017. Polymer notes are made from polypylene film, which is then coated with ink before being embedded with security features.

Advocates for plastic notes claim the new cash would be more safe and stay more clean than the current form of currency, which is made from cotton paper.

It is also claimed plastic tender would last two and a half times longer than the existing supply of notes, and be far less absorbent. At present, the 2.9 billion notes in circulation are so tainted by drugs like cocaine that police do not bother testing seized notes for banned substances.

But any switch to plastic notes could spell the end for Britain's distinctive currency, by shrinking notes in line with overseas versions.

However, this could be good news for anyone who has struggled fruitlessly to make a machine accept a note. Making the bills smaller would make it easier for them to be accepted at places like train stations.

Charles Bean, deputy governor of the Bank of England, said: "Polymer banknotes are cleaner, more secure and more durable than paper notes. They are also cheaper and more environmentally friendly.

"However, the Bank of England would print notes on polymer only if we were persuaded that the public would continue to have confidence in, and be comfortable with, our notes.

"The results of the consultation programme on which we are embarking will therefore form a vital part of our assessment of the merits of polymer banknotes."