Here’s a thought to stir the synapses. There is enough value locked away within the NHS’s huge databank to fund at least half of the £20bn promised by Theresa May in additional funding for the health service.

As one of the most comprehensive health services in the world, the NHS has data going back decades on millions of patients covering just about every illness. For researchers working in pharma or on the next generation of medical devices, such information is gold dust. Used properly and sensitively – and with patient consent – health data could help create many new treatments and save lives.

Indeed, Sir John Bell, professor of medicine at Oxford University and author of last year’s government commissioned life sciences industry review, argues that the use of NHS patient records could drive the development of powerful algorithms which could transform healthcare, and seed an “entirely new industry” in AI-based diagnostics.

Rather sensibly, Sir John also called on the government to investigate access to this data, and to examine the ownership of algorithms which are then developed using these records. It’s self-evident but not always understood – the value lies within the datasets used to train algorithms on tasks ranging from speech recognition to diagnosing diseases rather than the machine learning being applied.

But one of the problems in tackling this tricky issue is that NHS Digital is valued at zero in the government’s balance sheet. Early estimates suggest that even on conservative valuations the data could be worth at least £10bn.

More pertinently, insiders say the Treasury has no plans to change its zero valuation despite the decision to launch a wide-ranging Balance Sheet Review to look at the country’s ‘intangible assets’ such as NHS data. They say the Treasury has decided not to put a value on NHS Digital because doing so might send alarm signals to the public suggesting that patient records are to be commercialised, sold-off to the highest bidder. You can imagine the headlines now – private companies to profit from public misery.

If so, this is short-sighted. Opening up or sharing access to the NHS could be of great value, not just to patients but to the NHS itself which could, theoretically, be allowed to borrow on the open market to fund new ventures or state-of-the art equipment.

You could also argue that the NHS’s data is already being used commercially, but not in the sense that most people would immediately reach for. Several NHS trusts are already working with companies such as Google’s artificial intelligence arm, Deepmind, on new medical devices. In such cases, the data is not sold – it is given by the NHS on an anonymous basis with patient consent and strictly for health uses. In return for the data, the NHS gets a free pass to Deepmind’s software for five years. There are other models – some companies are giving the NHS equity stakes in return for data.

Looking at the hidden assets locked away in the health service is perhaps the most sensitive of the areas being investigated by HMG for the latest Balance Sheet Review launched last year by the Chancellor.

At the last count, the UK’s balance sheet had £1.7 trillion of assets and £3.7 trillion of liabilities. What the Treasury’s review hopes to do is discover if there are more effective uses of state-owned holdings, find out if there are areas which can be improved, such as the return on investments, as well as cutting liabilities.

On recommendations from the Public Account Committee, the review is focussed on exploring the potential for driving greater value from intangible assets and intellectual property. Officials at the Treasury and the Cabinet Office are now working flat out getting up to date valuations on the ‘intangible assets’ from individuals in the 6,000 different state departments ranging from the Ministry of Defence to Education.

Previous examples of where the government has earned revenue from being involved in private business include Axelos, a joint venture with Capita, which now exports training schemes such as the well-known Prince 2. First designed in Whitehall, these training schemes are sold to private sector clients from Pfizer to PA Consulting and around the world.

Another example is Cambridge Antibody Technologies, a biotech company created with intellectual property from the government controlled Medical Research Council. When CAT was started, the research council was given a license in return for an equity stake: CAT was sold for £700m in 2006 to Astra Zeneca with the government earning a nice slug.

Finding the Axelos and CAT companies of today is the Treasury’s new challenge, and a timely one ahead of the post-Brexit world. It’s a big job – finding the hidden intangibles, protecting them and commercialising them is not for the timid.

Philip Hammond is due to update us on the review in the Autumn Budget. If the Treasury is to make it worthwhile, it must include a valuation for the NHS’s data bank as one of the country’s most notable assets.

Hiding away from the issue will only make a suspicious public even more weary about the private sector encroaching onto the NHS. Far better for Hammond to be the one to spark a much-needed public debate about how such sensitive information can be kept private, but also used to save lives.