Crashing out of the EU on 31 October would have serious implications for hospitals, patients and pharmacies, with shortages of some medicines within weeks, MPs have been told by the pharmaceutical industry.

Critical and short shelf-life medicines – some of which may need to be refrigerated until they are consumed – would be most vulnerable in a no-deal scenario, parliament’s Brexit select committee heard on Wednesday.

“We would expect medicine shortages and a lot of price rises for the NHS pretty quickly and some shortages in some constituencies for sure,” Martin Sawer, the executive director of the Healthcare Distribution Association, said.

Counterfeit and substandard drugs could also find their way into pharmacies if the UK was forcibly detached from a new system introduced by the EU in February requiring all medicines to have a unique barcode, Sawer told the committee.

“If we leave with no deal, we could be unplugged from that system and therefore medicines in the UK we believe could be less safe because there is evidence already of organised crime trying to get into the regular prescription market. They have already picked up some packets through this new system in Holland, which often [supplies] the UK,” Sawer said.

He said the six-month stockpiling arranged by the government was continuing to be maintained with stock rotated as it went out of date.

The prospect of dubious medicines finding their way into the supply chain is a fresh challenge raised by the industry since no-deal stockpiling plans were put into action by the Department of Health and Social Care last September.

Sawer’s remarks come as Boris Johnson, the frontrunner to become the UK’s next prime minister, refuses to take no deal off the table, insisting in the BBC TV debate on Tuesday night that the country had to leave on 31 October.

Steve Bates, chief executive of the BioIndustry Association (BIA), also warned that the UK would be less prepared for a no-deal Brexit as the deadline for exiting the EU was only 101 days from the day the new prime minister was to be selected if the Conservative party process ended as scheduled in July.

The Conservative MP Craig MacKinlay suggested their warnings were more “project fear” from the medicine industry.

He questioned whether the country should really believe that if the UK had money to spend medicine manufacturers “would somehow not want to take our money”.

That scenario, he suggested to Sawer, “was somewhat fantastical”.

“We would expect some critical shortages probably in the lower volume medicines, not the everyday ones which are stockpiled,” said Sawer.

His association represents 10 distributors that deliver 2.5bn packages of medicine every year through 54 warehouses to every chemist, GP and hospital in the country.

He said that any delays in the “short straits” and Channel ferries would affect that supply.

“If we don’t get the product into the UK in the first place, then we’ve only got about two weeks’ stock in the wholesale sector that can go to pharmacies and hospitals,” he said.

Sawer said the Department of Health and NHS planning around stockpiling was “fantastic” and not to be faulted.

However, Sawer explained that shortages could occur even now when the UK was a member of the EU, citing shortages in Epipens last year. The supply of the adrenaline injection pen used by people with severe and life-threatening allergies had been hit because of a fire in a factory, he said.

Prices of medicines could also rise in the event of a no-deal Brexit, MPs were told. Photograph: Alamy

To overlay a system with logistical problems when the consequences of disruption in the supply chain was already critical was a risk the pharmaceutical industry could do without, he said.

“In medicines you have to get it 100% right. It’s not like supermarkets or car parks. You can’t delay that [supply chain] for some critical medicines, that’s our concern,” said Sawer.

Bates told MPs that building a British alternative to the current system was impossible to do in the near term as every step of the pan-European supply chain was regulated.

“Building a regulated manufacturing process would take years … it does take years. We are looking at 130 days to the October deadline. Moving at that pace is undoable,” he said.

Bates told the committee that government stockpiles were being maintained but warned that if trade barriers pushed costs up, generic drug suppliers might be reluctant to continue operating in the UK.

“We believe them to be more volatile because they are dependent on prices. Unless prices go up the medicines might not come to the UK; the manufacturer might not want to supply to the UK because the prices are too low,” he said.