Looming disruption to the flow of medicines after Brexit means Britain must seek to stay under EU regulation, senior Government figures have conceded.

Ministers are already pushing for the chemicals and aviation industries to remain under Brussels supervision – despite it clashing with Theresa May’s pledge to end oversight by the European Court of Justice (ECJ).

Now three leading Government figures have told the Financial Times that Britain will also need to stick with the EU’s rules on standards and safety for medicines.

The move follows a stark warning by the drug giants of “significant disruption to the supply chain for medicines” and that customs delays would damage “time and temperature sensitive” materials.

Meanwhile, Britain's biggest drugmaker said it would have to divert up to £70m from developing new cancer drugs in order to prepare for the impact of Brexit.

Glaxo-SmithKline (GSK) estimated that 1,700 of its products would be directly affected by the need for new regulation processes and approval systems – leaving less money for clinical trials.

Staying under EU regulation would be welcomed by the industry, but would be a headache for Mrs May if it crosses her “red line” that the ECJ must play no role in settling disputes.

Furthermore, Britain will lose 900 skilled jobs when the body regulating the sale of drugs, the European Medicines Agency, is required to move from London to Amsterdam – because of Brexit.

One Government official told the Financial Times that the ECJ red line had been blurred and was “not quite so rigid now”.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

Sarah Wollaston, the Conservative chairman of the Commons health committee, has said she hoped that “common sense” will prevail on medicines regulation.

However, Michel Barnier, the EU's chief negotiator, has warned Britain it cannot “cherry pick” parts of the EU single market it wishes to remain within.

The Association of the British Pharmaceutical Industry (ABPI), the body representing the UK's £63bn life sciences sector, has led criticism of the potential impact of Brexit on the flow of medicines.

Drugmakers AstraZeneca, Johnson & Johnson and Roche and Merck also set out their concerns in evidence submitted to an investigation by the Commons business select committee.

The fears threaten to cast a shadow over the Government's launch of a deal giving millions of pounds worth of support for life sciences firms, under the Prime Minister’s industrial strategy.

Steve Bates, chief executive of the UK's BioIndustry Association, said, late last year: “Businesses now need certainty. The best way to do this is by an early agreement to a transition timeframe and continued close regulatory cooperation.

“We must now ensure Brexit does not disrupt the safe supply of vital medicines to tens of millions of families in the EU 27 and the UK.”