The boss of the outsourcing firm Serco has defended its “extraordinary” work in setting up the NHS coronavirus test-and-trace system, amid calls for the £45.8m contract to be cancelled. Critics of Serco’s involvement have pointed to its mixed record on public works, the use of subcontractors and a blunder last month in which it inadvertently revealed the email addresses of contract tracers recruited to assist in the UK government’s “test, track and trace” strategy. Rupert Soames, the company’s chief executive, acknowledged the scheme was not perfect but said criticism was largely motivated by ideological opposition to private companies running state services. “It’s absolutely true that if you stand up 10,500 people, mostly working from home, there are bound to be issues and teething problems with technology but a lot of that noise has settled down,” he said. “I understand that there are some people who philosophically do not believe the private sector should be doing this sort of thing. “They’re never going to agree to us doing anything but anybody fair-minded would say it’s a remarkable achievement. What we and our partners have done is nothing short of extraordinary.” Much of the work has been subcontracted to smaller companies, according to Private Eye, raising questions about government oversight of how staff are managed and the quality of their work. Soames said: “We are responsible for them and the government knows exactly who they are. We’re completely transparent about them. It just means the government can deal with one company and we organised the subcontractors.” The Serco chief executive spoke to the Guardian after the company released an upbeat financial update to the stock market, saying work lost because of the pandemic had been replaced by contracts that came about as a result of it. These include drive-through coronavirus testing and services provided by the Department for Work and Pensions to vulnerable people. The test-and-trace scheme is the largest of Serco’s coronavirus-related contracts and involves monitoring those who have contracted the disease and anyone they have been in contact with. Designed to suppress a second wave of Covid-19 deaths, it has been rolled out across England with the help of 25,000 contact tracers, some of whom work for other companies. The Guardian revealed this month that the system it is not expected to be running smoothly until autumn. A leaked email from Soames to staff ignited concern about Serco’s long-term motives for accepting the contract. In the email he said the contract would “go a long way in cementing the position of the private sector companies in the public sector supply chain”. Explaining the email to the Guardian, Soames said: “It’s not a cunning plot to wheedle our way into the NHS, we’re very active in the NHS already. I was trying to say that we will be crucified if we get this wrong, quite rightly, but if we do it well maybe people will say that they did it well so it [private sector involvement] is a good thing.” Serco has been a lightning rod for criticism of outsourcing amid scandals including overcharging the Ministry of Justice for electronic tagging of prisoners who were either dead, in jail, or had left the UK.