The director of the Wellcome Trust has warned that resistance of disease to antibiotics has reached a tipping point at which it could creep into the UK almost without notice.
Prof Jeremy Farrar said the effects would be gradual and would be seen not just in resistant new infections but in everyday medical practice and the treatment of everything from diabetes to minor wounds at risk of turning septic.
Having worked in Vietnam for the past 18 years Farrar said he had already seen firsthand resistance to drugs in the shape of tuberculosis that had spread from patients' lungs to their brain.
"This is happening now," Farrar told BBC Radio 4's Today programme. "It's been happening for the last decade or so or more and it will continue to happen. What we will see is people actually spending longer in hospital, patients getting sicker and having complications and dying and it will creep up on us almost without us noticing.
"This will not be the sort of contagion-like event of somebody landing from Hong Kong in London with a pneumonia that is emerging that we've all feared. This will creep up on us insidiously, and of course that's in many ways more difficult to cope with."
He said there had been a "golden age" of antibiotics but complacency had set in in the 1970s and 1980s when there could have been more investment and antibiotics could have been used better, for example in combinations, to prevent the development of resistance to them.
"We're watching evolution happening," he said. "The viruses, the parasites have a pressure put on them from the drugs. They want to respond to that by surviving and not being killed by these antibiotics so therefore they evolve in ways that make them resistant."
Farrar said that 20 years ago there had been 18 companies in the commercial sector working in the field of antibiotics but now there were just four, and consequently only five new classes of antibiotics had emerged in the past 10 years.
He called for more imaginative ways to incentivise the pharmaceutical industry, for example through changes to patents, and for regulation around clinical trials to be eased. He said access to antibiotics needed to be regulated as they were available over the counter at low cost in many countries.
"No government can do this on its own because this is a truly global issue," he said. "This is getting to the tipping point where you will start to see this in you and your families and we will start to see this not in infections many, many miles away but here in London."
Last year the chief medical officer, Dame Sally Davies, described what she called an "apocalyptic scenario" where people going for simple operations in 20 years' time would die of routine infections "because we have run out of antibiotics".
Farrar said he was not presenting the crisis in apocalyptic terms but recalled the impact of HIV as an example of when a disease emerges that has no antibiotic for it.
"It's etched on my mind 30 years later," he said. "Young people, predominately male at that time, coming in and dying withing days, weeks and months of their infections because we had no way of treating it, and that is a risk that's really worth being concerned about coming back. Even in HIV we run the risk of returning at some point in the future to resistant HIV and that would be truly devastating."