Bill Woodrow and Martin Jennings have been selected from a shortlist of eight artists to create a memorial to Jamaican-born Crimean war nurse Mary Seacole outside St Thomas' Hospital.
An announcement of the chosen artist was due to be made on Wednesday at the Guards Museum in Birdcage Walk but Baroness Amos, chair of the selection panel, revealed that two artists' proposals are still under consideration.
They are Bill Woodrow who is proposing an abstract sculpture and Martin Jennings who has designed a bronze statue backed by a large disc.
The memorial is intended to be installed in the grounds of St Thomas' Hospital at the southern end of Westminster Bridge.
"Mary Seacole was famous and immensely popular in the 19th century," explains Lord Soley, chair of the memorial appeal.
"The troops coming back from the Crimea had concerts and raised money for her because she returned bankrupt and had to leave all her belongings there.
"She is a classic example of Britain in the 19th century where people – particularly from an ethnic minority background like her – did have to overcome hurdles but they didn't give up.
"They were both courageous and determined and they caught the mood of the nation.
"They were popular – but also brave and determined – and that's why we need a memorial to her."
Lord Soley believes that St Thomas' Hospital, with its links to Florence Nightingale, is the right place for such a memorial.
"Mary Seacole was an early example of a nurse who went onto the battlefield – literally picking up soldiers under shell fire – and nursing them."
The appeal still needs to raise £400,000 to build the memorial which could be completed by the end of 2010 and is due to be unveiled by Princess Alexandra.