While successive governments have stressed that the UK is a superpower in life sciences, in the eyes of one of the country’s biggest pharmaceutical companies, the US is the best place to invest.

The boss of the vaccines and medicines giant GSK, Dame Emma Walmsley, has told the BBC the company will invest $30bn (£23bn) in the US by the end of this decade.

The cash injection across the pond comes as other major drug makers have pulled UK projects worth billions after years of frustration over NHS drug budgets and pressure from President Donald Trump to set up production in the states.

And despite a new deal which will see the NHS pay more as part of a zero tariffs deal on shipping UK pharmaceuticals to America, Dame Emma is not going to “shy away” from GSK’s US investment plans.

The US is where the pharma giant makes more than half its turnover and is “still the leading market in the world in terms of the launches of new drugs and vaccines,” she says.

Alongside China, it is “the best market in the world to do business development”.

GSK’s latest stateside investment drive followed US pharmaceutical company Merck – which is called MSD in Europe – scrapping a planned £1bn expansion of its UK operations.

UK drug maker AstraZeneca has also announced it is pausing a planned £200m investment in a Cambridge research facility while ploughing tens of billions of dollars into the US.

Other drug companies have also said there is little appetite to invest in the UK, which successive governments have insisted is a life sciences superpower.

Dame Emma, who will leave GSK in January after eight years at the helm, stressed that GSK remains committed to the UK, noting that the interview was being carried out in its new global headquarters in London.

“No one should be deluded that the UK is going to be a massive scale market, a domestic market, but it can be an exporter of innovation in life sciences,” she says.

“For GSK, it’s 2% of our sales are here. More than 50% are in the US. But we’re very heavily invested, and remain committed to being invested in terms of manufacturing and research and development.”

Despite challenges facing Britain’s pharmaceuticals industry, Dame Emma welcomes the deal to scrap tariffs on UK drug shipments to the US as “a step in the right direction” for Britain.

The deal means the UK will pay more for medicines through the NHS – in return for a guarantee that US import taxes on pharmaceuticals made in the UK will remain at zero for three years.

Dame Emma says it is a welcome reversal of a long term decline in the portion of the NHS budget spent on medicines compared to other countries’ health systems.

The move, she suggests, will encourage the kind of innovation that supports ground-breaking new medicines, such as GSK’s new asthma drug which can be taken twice a year and could slash hospital admissions by 70% for serious asthma sufferers.

GSK hopes the new treatment will be approved for use by the NHS within weeks.

Asked about the health of the UK, Dame Emma says there are “social demographic root causes” for its decline.

She says health outcomes vary widely depending on where you live: “You can probably get a 10 or 15-year difference in lifespan prospects depending on which postcode you’re in.”

Dame Emma pointed to British diets and a lack of education around nutrition as part of the problem.

“I think there’s no question that the food system is fundamentally something we need to look at harder.”

Dame Emma also opened up about the differences she has experienced between the NHS and the private healthcare system in the US, having given birth in London, Paris and twice in New York.

“Both the experience of childbirth and all the follow up that happens afterwards are very, very different,” she says. “Anything from the advice you’re given.. .the frequency with which you are expected to be visited, how long you are in hospital and what kind of follow-up advice.”

Dame Emma added what matters is the balance of price, access and outcomes, and that the NHS still has “work to do” on getting the balance right.

Dame Emma, who also sits on the board of Microsoft, says the world is on the cusp of major advances in health science thanks in part to advances in AI which promise to accelerate innovation

“90% of the projects in our industry don’t work, they take a decade and cost billions. Getting to a place where you just double that to you know, instead of 10% working, 20% working will completely change the trajectory of innovation.”

In the end, she adds, few things are more important than health. “It is one of the few things that every single person on the planet ends up caring about.”