The long-term crisis in NHS finances will be laid bare next week when the health service reveals it is facing a £30bn hole in its budget – as a prominent Lib Dem peer suggests charging people to see their GPs.

Tim Kelsey, NHS England's information director and a former Cabinet Office adviser on data, said the health service faced a £30bn funding gap by 2020. In an interview with Health Service Journal he said: "We are about to run out of cash in a very serious fashion."

He said that next week NHS England would be "publishing a call to action". The document – entitled The NHS Belongs to Us All – is expected to make the case for significant changes to the way hospitals operate. "The financial context is, and our analysis will disclose, that by 2020 there will be a £30bn funding gap in the healthcare system."

NHS England's predictions appear to be based on work by the Institute for Fiscal Studies. Last year it calculated that if NHS spending was left to continue to soak up resources at its long-term rate and other on-health public spending is kept at 1% a year, then the funding gap would be about £30bn. When contacted NHS England confirmed that it would be publishing a report next week. "We are not in a position to say more at this stage," it said.

Lady Williams – one of the champions of the health service's "free at the point of use" ethos – on Friday called for a rethink over the way the system is funded. In an essay for the Nuffield Trust, a thinktank, Williams said: "There might be a case for at least considering a nominal charge for GP appointments … It might get people to value the service." She also suggests that wealthier pensioners should start paying for the NHS. Currently pensioners do not pay. However, Williams said: "You could also have a nominal charge for prescriptions for older people, with appropriate exemptions. An awful lot of people do actually have quite substantial pensions in addition to the state pension."

Andy Burnham, the shadow health secretary, warned that the government's obsession with "top-down reorganisations" had sapped the ability of the NHS to become more efficient. "The government made a monumental mistake when it distracted the NHS with a huge top-down reorganisation when what it needed instead was to focus all its energy on saving money," he said.

"The result has been two wasted years in the NHS where people have been thinking about their jobs instead of making the service changes we need. To make matters worse, at least £3bn has been wasted in the process. This government must be held responsible for failing to get ahead of this future funding gap."

Kelsey also revealed that the UK and US governments were currently working on a common standard of certification for health companies to make it easier for them to access both markets. Some critics of the government's health reforms say they were conceived as a "necessary prelude" to a trade agreement with the US.

The NHS director confirmed that "one of the things that we agreed with the US government which will be hopefully signing at the G8 meeting in November is that we want to make it as easy as possible for small businesses to get access to both the US and the UK market places".

Kelsey added: "To do that we want to have some common standards. We will be working on a standard of certification so that you can be in the digital hospital marketplace or the apps marketplace and you only need to sign up to one certification scheme."