The government’s coronavirus testing programme is dealing with a backlog of 185,000 swabs, with tests being sent to Italy and Germany as local labs are overwhelmed. Not even a week after the government was forced to apologise for continuing delays to Covid testing, the Department of Health and Social Care insisted on Sunday that the capacity of the NHS test-and-trace system was the highest it had ever been but there was a “significant” demand for tests. This includes demand from people “who do not have symptoms and are not otherwise eligible”, the DHSC said. Leaked documents revealed the 185,000 backlog and the fact that tests are being sent to German and Italian laboratories for processing, according to the Sunday Times. The documents also show there has been an increase in tests being voided. On Saturday, exasperated parents in England complained of a test-and-trace system still in “shambles”, with some struggling to secure testing slots for their children who have developed symptoms since returning to school. Although the head of NHS test and trace apologised on Tuesday to people in England who have either been unable to secure a coronavirus test or been told to go to drive-through centres hundreds of miles away, many people trying get a test this week were met with an error message telling them to try again and warning them not to call the helplines. The DHSC said it plans to rapidly expand capacity in the coming weeks and that new technology would be employed to process tests faster. The clinical diagnostics company Randox reportedly disposed of 12,401 used swabs in a single day on 2 September, and has voided more than 35,000 used test kits since the start of August. In a statement, Randox said a small minority of samples may be voided for reasons such as leaking or damaged tubes, or because they have expired. “Those being tested are made aware that samples only remain valid for a limited period once collected, and those periods of validity are fully understood across the planning and logistic process. Randox have no responsibility for the logistics of sample delivery to laboratories,” the statement said. The transport secretary, Grant Shapps, said on Thursday that 1.2m tests were being carried out per week, adding that there was capacity for 300,000 per day. The government no longer publishes daily testing figures, but the latest available figures say 175,687 tests were reported on 2 September, while the estimated total capacity reported by laboratories for that day was 369,937. Jonathan Ashworth, the shadow health secretary, said: “Ministers promised us a world beating test and trace system, but instead they have overseen a complete fiasco. “People ill or with a sick child desperate for a test will be astonished that tests are piling up left unprocessed, or even thrown away, because of errors in transportation and swabbing, while at the same time we are testing less than capacity. “This really is ministerial incompetence at a whole new level.” In May, it emerged that about 50,000 coronavirus test samples had to be sent from the UK to the US after “operational issues” in the lab network led to delays in the system. At the time, the DHSC said sending swabs abroad was one of the contingencies to deal with teething problems in a rapidly expanded testing system. A spokesperson said: “NHS test and trace is working and our capacity is the highest it has ever been but we are seeing a significant demand for tests including from people who do not have symptoms and are not otherwise eligible. “New booking slots and home testing kits are made available daily for those who need them and we are targeting testing capacity at the areas that need it most, including those where there is an outbreak, and prioritising at-risk groups. “Our laboratories are processing more than a million tests a week and we recently announced new facilities and technology to process results even faster. If you do not have symptoms and are not eligible to get a test you can continue to protect yourself if you wash your hands, wear a face covering and follow social distancing rules.”