When, in March, Britain went into lockdown, its inability to monitor and respond to Covid-19’s rapid spread was most starkly exposed when compared to Germany. The Bundesrepublik’s superiority was especially evident in the statistic that mattered most – fewer Germans were dying of the virus than Britons.

Among the reasons proffered to explain Germany’s better performance, the most obvious seemed to be its ability to mass test its citizens. By contrast, the lack of an equivalent diagnostic sector in the UK meant that as early as 12 March (two weeks before lockdown) British efforts to test and trace the virus’s spread were officially called off because there was not even a fraction of the capacity available for it to make any appreciable difference to the virus’s spread.

If Boris Johnson’s newly elected government had failed to develop a mass diagnostic capacity in the three months since its general election victory then it was an omission that carried on the long tradition of all its predecessors. But great leadership rises to a challenge and there was broad political as well as expert consensus that testing and tracing was the most likely means to limit Covid’s spread until such time as a vaccine was found, approved and deployed.

The resulting national system, NHS Test and Trace, was accorded no favours by the prime minister’s baptismal promise that it would be “world beating.” With every failure that has followed, Johnson’s boast has been flung back at him and at Baroness Dido Harding, the former TalkTalk CEO and Sainsbury’s director, entrusted in May with its development.

Lowered expectations would have generated a better appreciation of what Harding and her team have achieved. At the end of March, the UK had capacity to conduct 80,000 tests a week. Health workers were duly prioritised. Now, half a million people a day can be tested. Creating capacity that exceeds demand in the midst of a pandemic would normally be considered an achievement at least on a par with the rapidly fitted-out (of as yet unused) Nightingale hospitals.

As recently as September, the media was reporting cases of Londoners being advised that their nearest available test centre was in Inverness. Now there are 600 sites across the country and the average English resident is less than three miles away from a testing centre. As Harding pointed out on Tuesday to the Commons science and technology and health and social care joint committee, in the space of five months she has overseen the construction from scratch of an organisation bigger than Asda.

By European standards this is impressive. Between May and October, the UK’s testing capacity increased by 514 percent. During that time, Germany has also done well, increasing (from a higher base) testing capacity by 351 percent. Spain has increased its capacity by 235 percent, Italy by a little less. During this time, Europe has lost much of its early belief that test and trace offered a workable alternative to re-imposing lockdowns. France’s system is failing, its accompanying StopCovid app having flopped. Now Germany – the original test and trace role model – has admitted it does not have the capacity to keep on top of the virus’s spread.

Against this backdrop, the lampooning of Baroness Harding and insistence that NHS test and trace is a national embarrassment may seem hard to fathom. If only the prime minister had boasted of a Europe leading system, rather than a world beater, he would have been difficult to contradict him.

Yet, of course, the failure is not in the creation of a mass diagnostic service – which has been created with extraordinary speed – but in the tracing of contacts and the enforcement of quarantine. Failures in these provisions mean that the £12 billion invested has not delivered what should have been test and trace’s aim – an alternative to a second lockdown.

To be useful, test and trace needed to be able to process the results speedily (currently about 60 percent of test results are communicated within 48 hours), and ensure that listed contacts of the virus carrier were contacted and instructed to quarantine. Sage calculated that 80 percent of close contacts need to be reached and to quarantine accordingly. In reality, at best, 60 percent of positive cases are being reached and only an estimated 20 percent of those who should be quarantined are fully doing so. So the scaling-up of NHS test and trace has been impressive in everything except its effects.

It should not be a shock that so many of those who should isolate are not doing so. Fourteen days confined to home is more than a social inconvenience, it is a serious financial penalty to the low paid and zero hours contractors who cannot work from home. Understandably, many test-takers have been reluctant to name as contacts those close to them whose livelihood risk being harmed in this way.

If only the prime minister had boasted of a Europe leading system

Belatedly, inducements to make quarantine compliance more attractive have been introduced. A £500 isolation support payment is now offered to the low paid. Beyond this carrot, the stick takes the form of being called three times to check that those required to quarantine are indeed at home. Yet, effective enforcement is beyond government by consent in this country, requiring as it would fully surrendering personal liberty and data protection to an all seeing state, equipped to spy on every creak of the garden gate.

We now know – thanks to testing – that the vast majority of those who fear they have Covid symptoms do not have the virus. Testing also suggests that 40 percent of Covid carriers are asymptomatic. Until there is regular and comprehensive whole population testing, this is an insurmountable problem because if carriers do not spot symptoms they are less likely to seek a test and will therefore not realise they are spreading the virus. As for those that testing does identify, as Dido Harding conceded to the joint select committees on Tuesday, “it’s hard to isolate for fourteen days, particularly if you don’t feel unwell.”

A nationwide system that depends on tens of thousands of people putting aside natural behaviours when they feel fine and have other priorities in mind than sitting idly at home for fourteen days without break is going to struggle to reach its success metrics. It is unfortunate that in predicting the need for an 80 percent compliance rate for test and trace to be effective, Sage did not also advise that the human factor made reaching this target highly unlikely – or that the government would ask the question.

When the failure of individuals to fully comply with test and trace is pointed out, the Labour frontbench line has been to accuse the government of blaming the people, rather than their friend the Tory baroness, Dido Harding, who knows about telecoms and supply chains but not epidemiology. But in identifying fall girls and guys, the most strategically questionable decision was made not by Lady Harding (who is executing the brief given her) but by the department of health and social care.

For it was Whitehall that determined upon a nationally centralised system, drawing upon NHS and local government resources, but primarily outsourced (at great cost) to private sector providers like Serco and Sitel to run vast call centres. In choosing this option, the health secretary, Matt Hancock, rejected the alternative of building up the underpowered, but existing, local and community services. If it was not self-evident at the time, hindsight suggests the latter should have been key to the strategy.

Recipients assume that the incoming 0330 number is an unsolicited telesales call

Hancock’s decision was not entirely without logic. For instance, the centralised system is doubtless better at meeting provision for surges than a set-up wholly devolved to community level. An exact comparison between the success rates of community and centralised contact trace teams is misleading because the latter’s volume is so much greater. However, the fact remains that community services are achieving far higher tracing and compliance results than are being achieved by the national system.

Why should this be? Expert witnesses at Tuesday’s joint select committee suggested this was down to local authority employees having better local knowledge and the trust that this endangers. Local contact-tracing can better offer a wraparound service that proffers wider advice and this wins recipients’ trust. By contrast, those who need to isolate are typically not answering the phone to the national system’s centralised call centre staff. Recipients assume that the incoming 0330 number is an unsolicited telesales call and they do not even listen to the ensuing answerphone message (or they deduce it is a demand to quarantine and choose not to hear it). No amount of repeat calling seems to get around this barrier.

Dido Harding assured the joint select committee that the best solution is a mixture of national and local provision. Certainly, the initial belief in a centralised system has been replaced by greater involvement with local authorities. About half of them are now working in partnership with test and trace and a further 150 councils are about to join in.

Eighty percent of the cost of test and trace has gone on developing test capacity. Having created that capacity the switch to improving tracing ability is timely. Meanwhile, awaited are the results from the pilot scheme now underway of mass testing the Liverpool population. What picture of the virus’s spread will comprehensive testing of an entire community of half a million people provide and which testing methods used in the pilot scheme will perform best?

Pressing questions for the department of health and for the Treasury concern whether such saturation testing can be done nationwide and without unacceptable expense. What is more, there is now the possibility of different priorities interceding if the Pfizer/BioNTech vaccine is truly the Christmas present for which the world has been wishing. Test and trace’s failings may yet be overlooked if the British government can distribute the 40 million doses it has secured to the 20 million most vulnerable recipients, quickly and successfully. Given the need to store the doses at minus 80 degrees, the “if” becomes the vital qualifier in that expectation.