Banknotes featuring King Charles will be issued for the first time on 5 June, prompting the Bank of England to warn businesses that they need to make sure their machines are ready to accept them.

The portrait of the king will appear on existing designs of all four UK banknotes – the £5, £10, £20 and £50. His image will be on the front and also in the see-through security windows. However, the other design and security features will remain the same, with no other changes to the existing look of the notes.

However, the rollout of the notes may be a little more low-key than some were anticipating, and that may be linked to the king’s longstanding interest in the environment: he gave a speech warning about the dangerous effects of plastic and chemical pollution in 1970, when he was 21.

The Bank of England said: “[The notes] will only be printed to replace those that are worn and to meet any overall increase in demand for banknotes.” It added: “Our approach is in line with guidance from the royal household to minimise the environmental and financial impact of this change.”

Polymer banknotes were introduced by the Bank in 2016, ending 320 years of paper money in Britain.

The existing notes featuring the late queen will remain legal tender and will be in circulation alongside the new notes. That means people do not need to exchange or use up the banknotes featuring Elizabeth II. There are more than 4.6bn sterling bank notes in circulation with the queen’s face on them, worth a combined £81bn.

The announcement marks the start of a series of changes that will need to be made to many machines that accept, sort or check banknotes to ensure they can handle the new note designs.

The Bank of England wants all affected businesses – from shops, rail firms and car park operators to casinos and vending machine companies – to have completed any necessary updates by 5 June.

“If your business uses or is responsible for any machines that accept, sort or check banknotes, you need to plan for their adaptation,” said the Bank. In preparation for the change, banknote equipment manufacturers were releasing updates for firms to install now, it added.

When Elizabeth II acceded to the throne in 1952, the monarch did not feature on banknotes. That changed in 1960 when her face began to appear on £1 notes.