The chairman of the trust which runs SE1's two hospitals has issued a pre-election warning that the National Health Service faces a "major funding gap".
Sir Hugh Taylor has cautioned that "eye-watering" cuts would be necessary to reconcile political commitments and the demand for treatment.
In his chairman's report for next week's meeting of the Guy's and St Thomas' NHS Foundation Trust board, Sir Hugh says: "As I write, electioneering is in full swing; the NHS is at the centre of the debate; and the outcome of the election is uncertain.
"From the perspective of this trust, of our local NHS, and of our fellow teaching hospitals across England, one thing is certain.
"There is a major funding gap in the NHS ‐ and an absence of strategies or policies which show how any incoming government would address the gap between such funding promises as are being made and the eye watering scale of efficiencies that would be required to match the current and potential demand in the system, particularly if current standards on patient safety and access to services are to be maintained.
"Continued uncertainty over the payment system for specialist services, combined with increasing pressure on our emergency and elective services, have made it difficult even for this trust to set a budget with confidence for the current year; and the prospects for 2016/17 are even more uncertain.
"This has been a major pre‐occupation for our board over the last three months.
"Our staff are continuing to respond magnificently to the continuing search to improve the efficiency and productivity of this trust, while maintaining the high quality standards to which we are committed; and we are fortunate in having strong and supportive local commissioners.
"But I and my senior colleagues, together with the boards of other leading organisations will be impressing on the incoming government, NHS England and Monitor, the need for urgent action to sort out the future tariff for specialist services and to set a credible funding strategy for the NHS as a whole, consistent with the five-year forward view published by NHS England last year – on the substance of which there is broad consensus."
Sir Hugh's note of caution carries particular weight; before his appointment as chair of Guy's and St Thomas' he served as permanent secretary at the Department for Health, so has a unique insight into Government health policy at the highest level.