The Conservative party’s leadership election delayed crucial plans to secure the flow of key medical supplies in the event of a no-deal Brexit, senior government officials have revealed.

Despite the tight deadline to secure supplies before a possible no-deal Brexit at the end of this month, the summer contest to replace Theresa May set back plans to secure extra freight capacity by almost three weeks. The revelation came just days after warnings that no deal still poses risks to the NHS and care homes, despite extensive government planning.

Whitehall officials have been working on plans to safeguard medical supplies by securing freight capacity away from the Channel crossing. Officials have identified the need for 2,326 heavy goods vehicle spaces per week to secure crucial supplies and need it in place by the end of the month.

The admission that the leadership contest interfered with the critical work came from Bernadette Kelly, the most senior civil servant at the Department for Transport. She conceded the formal process for securing the freight capacity was launched at the end of July, 19 days late.

“The work on this procurement probably started back in June,” she said. “It is probably fair to say, through June and July, the time of the Conservative leadership election, there was rather more reluctance than might otherwise have been the case for ministers to take firm decisions about no-deal planning when they were anticipating a new government being appointed very soon. The consideration was that some decisions were more appropriately taken by new ministers.

“As we got closer to the point of being in a new administration, understandably, the reluctance to commit to very firm decisions grew. I should say, from an official’s perspective, we were always very conscious of the need to ensure that the procurement was proceeding at pace. That is why the very first piece of advice the new secretary of state received in the Department for Transport was advice that we should proceed immediately.”

The contracts are now due to be awarded on 12 October, giving very little time for further delays before the no-deal deadline.

Kelly was responding to MPs last week, as they questioned her on a report by the National Audit Office (NAO). It warned that ministers would not know if there were enough medicines, medical supplies or freight capacity to support the NHS if the UK left the EU without a deal at the end of the month.

Responding to the NAO report, a Department of Health and Social Care spokesman said: “We want to reassure patients that we are doing everything we can.” The government says it has mounted an unprecedented response to the difficulties posed by no-deal Brexit and that stockpiles were increasing each day.