The Bank of England has decided to continue using chemicals derived from animal products to make new plastic postcards, despite a protest.
A wide consultation without overwhelming majority of respondents said they were against using additives.
But the bank said the alternative to using palm oil raised environmental concerns and would cost Treasury an additional £ 16.5 million over the next ten years.
The government told the Bank that it did not believe a move would be worth the money for taxpayers.
Campaigners launched a petition last autumn after it emerged that the new 5-pound letter contained traces of a derivative of animal products.
The bank began a noise review and earlier this year decided not to scrap the notes, though said it would hold a public consultation on the production of future notes.
Now he said that after "careful and serious scrutiny ... there will be no change in the polymer composition used for future banknotes."
"The new £ 20 and upcoming fonts of £ 5 and £ 10 will continue to be made from polymers produced using traces of chemicals, usually less than 0.05%, eventually derived from animal products" , Said the Bank.
His consultations included field meetings with affected groups, technical judgments, commercial discussions and the commissioning of independent environmental research.
There were also answers from 3,544 people. Of these, 88% were against the use of animal products and only 48% against the use of those produced from palm oil.
But the Bank said it had to balance this "against other public duties and priorities" and other evidence it had gathered.
"The use of palm oil raises questions about environmental sustainability and the Bank's suppliers have been unable to commit to ensuring the highest level of sustainable palm oil at this time," she added.
"The bank fully recognizes the concerns raised by members of the public before and during the consultation, and has not made this decision easily."
