The Bank of England has released a list of scientists who have been nominated to feature on the new £50 note.
On the list are computing pioneers Alan Turing and Ada Lovelace, telephone inventor Alexander Graham Bell and astronomer Patrick Moore.
The Bank received 174,112 nominations, of which 114,000 met the eligibility criteria.
To be on the list, the individual must be real, deceased and have contributed to the field of science in the UK.
The list, which includes more than 600 men and almost 200 women, includes black holes expert Stephen Hawking, penicillin discoverer Alexander Fleming, father of modern epidemiology John Snow, naturalist and zookeeper Gerald Durrell, fossil pioneer Mary Anning, British-Jamaican business woman and nursing pioneer Mary Seacole and Margaret Thatcher, who was a scientist before becoming prime minister.
The late Baroness Thatcher studied chemistry at Oxford University and after graduating joined British Xylonite Plastics in 1947. Two years later she joined J. Lyons & Co in Hammersmith, west London, as a food research chemist in a role that involved testing the quality of cake-fillings and ice-cream, wrote biographer Hugo Young.
The politician has been credited with inventing soft serve ice cream - a product Lyons worked on - but "there is no firm evidence that Thatcher directly assisted in its invention", according to a Royal Society journal article.
Bookmakers William Hill have Stephen Hawking as the current favourite, with odds of 7/4, followed by Nobel-prize winning chemist Dorothy Hodgkin 4/1.
Ada Lovelace, Alan Turing and Alexander Fleming have odds of 5/1 and Rosalind Franklin, who made important contributions to the understanding of DNA, is at 6/1.
Further names will be considered up until nominations close on 14 December.
After that the decision will be considered by the Bank's Banknote Character Advisory Committee.
Paul Rincon, BBC News website science editor
The definition of eligibility for this list is pretty broad at the moment, but stricter criteria are likely to be applied once the names are considered by the Bank's committee.
Thus, while Margaret Thatcher's contributions to politics are considerable, it remains to be seen whether the committee will judge her an equally significant scientific figure.
Hers is just one of the names that some observers will think fall outside some of the stricter definitions of a scientist. But a broad definition of eligibility could assist the promotion of some figures that were overlooked by the establishment in their lifetimes, such as Mary Anning, who, without formal qualifications, helped document important fossil finds from southern England.
Those hoping for strong female contenders will find much to like about the list. But there are also inclusions that highlight the contributions of ethnic minorities and immigrants to British science.
The committee which draws up the shortlist will include space scientist Maggie Aderin-Pocock, author and genetics expert Emily Grossman, editor of the British Journal for the History of Science Simon Schaffer, and theoretical and particle physicist Simon Singh.
Nominations can include anyone who worked in any field of science including astronomy, biology, bio-technology, chemistry, engineering, mathematics, medical research, physics, technology or zoology.
There are currently 330 million £50 notes in circulation, with a combined value of £16.5bn, the Bank said.
A year ago there were doubts that the £50 note would continue to exist at all.
Fears that the largest denomination note was widely used by criminals and rarely for ordinary purchases prompted a government-led discussion on whether to abolish it.
The £50 note was described by Peter Sands, former chief executive of Standard Chartered bank, as the "currency of corrupt elites, of crime of all sorts and of tax evasion".
Nevertheless, in October, ministers announced plans for a new version of the note, to be printed in the UK, which they said would be plastic - so, more durable, secure and harder to forge.
Steam engine pioneers James Watt and Matthew Boulton appear on the current £50, issued in 2011.