More than 900 days ago, a slim majority of the British public voted to leave the EU. Many of those voters were tempted by a bold statement emblazoned on the side of a bus, promising riches for the NHS and with it, a boost to the nation’s health.

Now, with just 100 days to go until Brexit day, the claim of extra money for the NHS has been widely debunked and the dangers that leaving the EU poses to the wider economy, our health service, its staff and patients have been laid bare.

Back in June, at the British Medical Association’s (BMA) annual representative meeting, doctors from across the UK overwhelmingly passed a motion opposing Brexit and calling for a people’s vote on the final deal.

While hardline Brexiteers decry the interference of experts, it would be a dereliction of our professional duty – putting the interests of our patients first – to remain silent in this debate. Far from being the scare-mongerers, some would have you believe, we are simply providing evidence, as doctors who care for patients daily, about how damaging Brexit will be for Britain’s health.

As a member of the EU, Britain has access to myriad benefits provided by its shared institutions, meaning that the NHS can provide top-quality care, revered by its counterparts around the world. Likewise, Britain’s health expertise can be shared across Europe, meaning the health of the entire continent benefits.

From the free movement of highly skilled health workers, to collaboration on research and the smooth supply of medicines in and out of Britain, EU membership is key to maintaining and improving the health of the nation.

With 100 days to go, we are plagued with uncertainty; indeed, the only thing that is certain is that no type of Brexit will ever offer the same health benefits we currently have.

Take staffing for a start. Around 10 per cent of doctors in the NHS are from another EU country, and thanks to freedom of movement, patients receive high-quality care from this invaluable section of the workforce.

The government has been clear that this situation must end once we leave the EU, and recent BMA research revealed that Brexit is the key reason more than a third of EU doctors are considering leaving the UK. The Home Secretary this week proposed a salary threshold as part of long-term plans for managing migration, and while it may not eventually be the previously floated figure of £30,000 a year, anything close to that would affect a vast swathe of the wider NHS workforce coming from overseas.

What is apparent is that any future system will add unnecessary bureaucracy and barriers for the crucial healthcare staff who bring their skills and bolster the NHS workforce at a time of severe shortage.

Similarly, the system for mutual recognition of professional qualifications (MRPQ) makes it easier for doctors who qualified in one member state to practice in another, while the Internal Market Information System (IMIS) means each country’s regulatory body (such as the General Medical Council in the UK) can communicate extremely quickly with its EU neighbours – which is vital for guaranteeing the safety of patients.

In terms of medicines, the UK’s membership of the European Medicines Agency (EMA) means patients have timely access to new medicines and medical devices. To ensure this continues after Brexit, the UK’s medicines regulator will have to follow the EMA’s rules on medicines, but without the power to shape them. Likewise, our ability to influence cross-border efforts to combat infectious diseases will be gone. We will be demoted, at best, to mere observers.

Meanwhile, in Northern Ireland, well-established processes of cross-border care, and the free movement of patients and doctors, are both in jeopardy.

The supply of radioisotopes – not produced in the UK but vital for cancer diagnoses and treatments – also relies on our membership of Euratom, which is itself intrinsically linked to EU membership. Outside of the EU, there is a real risk that the supply of these crucial lifesaving materials will be severely disrupted.

How did we get to a situation where cancer care is at risk because of a decision so heavily influenced by questionable claims, scrawled on the side of a bus?

The impact of Brexit reaches every corner of healthcare – and the issues discussed in this article are far from exhaustive. Therefore, it is absolutely imperative that the public is given a final, informed say on any deal, in a second referendum. Their health is quite literally at stake.

With 100 days until Brexit, the corridors of power are still consumed with infighting. Yet it will be those left waiting in the corridors of our hospitals and the waiting rooms of our GP surgeries that bear the real brunt of this current political chaos.

The writer is council chair at the British Medical Association.

The Independent.