The Bank of England (BoE) is asking the public to submit nominations of prominent British scientists to appear on a new £50 note.
BoE governor Mark Carney said the figure can come from any field of science but he excluded economists.
The current £50 note features steam engine pioneers Matthew Boulton and James Watt.
The UK's highest denomination note is the last to be redesigned and switched from paper to a more secure and durable plastic.
There is no shortage of individuals to nominate. Suggestions could include renowned physicist Stephen Hawking, who died in March, or Dorothy Hodgkin, who won the Nobel Prize in Chemistry in 1964.
Nominations can be made on the bank's website until December 14. A committee will create a shortlist from the recommendations, and Carney will make the final choice next year.
The bank says the individual must be dead, and real - to avoid a repeat of the process that saw the public choose "Boaty McBoatface" for a new research ship.
The bank is converting its notes into plastic to make them harder to counterfeit. A new £10 note with author Jane Austen went into circulation last year, and a £20 note featuring artist J.M.W. Turner will be produced in 2020.
The announcement that Churchill would feature on the £5 note, replacing 19th century social reformer Elizabeth Fry, raised the prospect that Queen Elizabeth would be the only woman featured on British banknotes.
The BoE subsequently said that the 19th-century novelist Jane Austen would appear on the new plastic £10 note, which it launched last year.