Patients could face long delays obtaining new drugs or be denied access to them altogether as a result of Brexit, a coalition of doctors, NHS bosses and pharmaceutical firms warns.

The NHS may find itself unable to access newly developed medications for up to a year compared with the other 27 EU nations once Britain leaves in March next year, they said on Monday.

Patients could lose out unless the government makes continued UK-EU cooperation on the supply of drugs a key priority in the second phase of Brexit negotiations and avoids a “no-deal” exit, according to a report from the Brexit Health Alliance.

The BHA includes the Academy of Medical Royal Colleges, which represents the UK’s 250,000 doctors; leading health charities; the NHS Confederation and NHS Providers, both of which lobby on behalf of NHS hospital trusts; and the Association of the British Pharmaceutical Industry, the trade body for the country’s drug developers and manufacturers.

“The UK’s plans to leave the European Union and the EU’s single market could have serious implications for patients’ access to medicines and medical technologies,” the report warns. Patients in both the UK and EU27 could suffer negative impacts from “the disruption in trade that could result from the UK’s exit from the EU, as well as in the event of lack of cooperation in the regulation of medicines and devices between the EU and the UK post-Brexit”.

It outlines a series of problems which could affect the UK’s ability to access drugs as a result of its loss of membership of the European Medicines Agency (EMA), a body of experts which approves all new pharmaceutical products so they can be given to patients in the EU. It is moving its headquarters and 900 staff from Canary Wharf in London to Amsterdam as part of Brexit.

“Potential disruption” to the supply of drugs in which the licences are held by EU countries could lead to the UK having to devise a new system for approving 978 drugs which have been authorised by the EMA since 1995, the alliance believes.

“It’s vital that the health of patients is prioritised in the second phase of negotiations. If not, patients in the UK and the EU could face delays in accessing potentially life-saving treatments,” said Aisling Burnand, chief executive of the Association of Medical Research Charities.

Despite having several bilateral trade agreements with the EU, Switzerland starts receiving new drugs an estimated 157 days after its members. Similarly, Canada and Australia often get new drugs between six and 12 months later than in the EU or United States. That is because drug companies target their new products at the largest market. While the countries covered by the EMA represent 25% of the world’s overall pharmaceutical sales, the UK accounts for only 3% of it.

The Office of Health Economics recently said that, after Brexit, 5-15% of marketing applications to use drugs in the UK could be submitted more than a year after the EU27, and that, based on Switzerland, Canada and Australia’s experiences, some medications may never come to the UK.

Sick children and patients with rare diseases could suffer in particular if Britain is no longer part of Europe-wide arrangements to promote the development of drugs for both groups, the BHA added.

“There are many aspects of the NHS that could be hit hard if a Brexit deal does not make the right arrangements, or if it is executed badly. As well as disruption to the availability of medicines, problems with customs and trade could push up prices and make the already large NHS deficit worse,” said Mark Dayan, a policy analyst at the Nuffield Trust health thinktank.

The Department of Health and Social Care rejected the BHA’s concerns. “We are committed to ensuring patients in the UK continue to access the best and most innovative medicines. Patient safety is our priority, and we will protect it through ongoing cooperation and a strong regulatory framework,” a spokesman said.