The head of the NHS in England has called on ministers to provide billions of pounds over the next three years to save the health service from a funding crisis.
Simon Stevens spoke out as he warned that the government's Comprehensive Spending Review, due to be unveiled in three weeks, may not provide a "workable" solution for the NHS.
Ministers have pledged to increase the health service's annual budget by £8 billion a year by 2020. That followed Stevens' 'Five Year Forward View' report, which said the NHS would deliver £22 billion-worth of efficiency savings over the same period.
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In an interview with the Health Service Journal, Stevens said most of the government cash will need to be "frontloaded" in 2016/17 and 2017/18 to fill a budget black hole.
He said: "For the NHS, next year and the year after are where the rubber will really hit the road.
"The Forward View maths was explicit that the health service needed frontloaded investment in 2016-17 and 2017-18 to manage current pressures, kick-start service redesign, and unleash major savings later in the parliament.
"We were also crystal clear that any further cuts in public health and social care would impose extra costs on the NHS over and above the minimum funding requirement."
Stevens added: "As of today, considerably more progress is going to be needed before we can say we have a genuinely workable NHS funding solution for 2016-17 and 2017-18, but spending reviews usually come down to the wire, so hopefully we’ll get there by 25 November."
George Osborne announced on Monday that he had so far reached funding settlements with three other Whitehall departments, but the Department of Health is not one of them.
A Downing Street spokeswoman said: "We have been very clear about the funding we have provided to the NHS."