Prof Tim Briggs, medical director of the Royal National Orthopaedic Hospital (RNOH) in north London, will challenge the former minister Tony McNulty as an independent candidate for Harrow East with the aim of securing the future of the institution.
The RNOH, which treats 60,000 patients a year, is in a state of disrepair and costs millions of pounds to maintain every year.
Prof Briggs has campaigned for nearly 15 years to secure money to rebuild the hospital on its current site in Stanmore.
But his lobbying has failed to secure the £60m needed from the strategic health authority, NHS London.
Mr McNulty holds the seat with a 4,700 majority.
Professor Briggs said he was giving the Government “one last chance”. If the Health Secretary Andy Burnham did not give him a firm commitment at a meeting this week, he would stand against Mr McNulty, he told the Independent on Sunday.
NHS London said: “It is clear that the RNOH NHS Trust provides a high-quality service but from an inadequate site. NHS London and Department of Health colleagues are currently reviewing the business case and the trust is responding to a number of points that we have raised for clarification."