The key to containing the Coronavirus – social distancing apart – is the Government’s test and trace scheme.

Enough tests should provide more information about the R rates that really matter: in other words, not a single national figure, but lots of local ones, which reveal where the virus is growing fastest and among whom.

It would also provide the basis, as we argued last Thursday, for a mix-and-match way out of the lockdown, with areas, towns and perhaps cities opening up where R is discovered to have fallen.

That in turn would allow the stalled engine of the economy to re-fire – at least to some extent, depending on the number of places in which R has fallen sufficiently, and the number of restrictions that can be lifted.

To be able to do this, Ministers will need enough tests and trackers to make such a plan practicable – or else, if Ministers shy away from local shutdown liftings, to manage a single national one in England.

Having spoken to Government sources, ConservativeHome can’t see any reason to believe that progress will be swift, or that Boris Johnson will opt for the area-based approach that would lift the lockdown faster.

First, tests.  The Prime Minister has spoken of the capacity to carry 200,000 tests by the end of the month.  That’s not the same as 200,000 actually being carried out.

Matt Hancock has done well to build a national testing industry from scratch, and Ministers are now able regularly to announce the delivery of over 100,000 a day at press conferences.

(Though again this doesn’t necessarily mean that 100,000 actual tests are being carried out, since that figure includes kits sent in the post and tests not sent yet to laboratories.)

And obviously, even 200,000 tests a day wouldn’t necessarily mean speedy progress.  The Government estimates that roughly 160,000 people have the virus at the moment, and that number can potentially go up.

In any event, this site was told yesterday that Ministers are “slightly backing off” that 200,000 target, such as it is – which suggests it won’t be reached.

There is then the second question of how many trackers will be employed to trace those with whom those tested have had contact.

Ministers say that they need 18,000, and Michael Gove was able to announce yesterday that it will hit its target of recruiting them by the end of the week.  That’s good news.

The NHS’s Business Services Authority is organising recruitment, and Serco will be one of the biggest providers – which won’t necessarily fill everyone with confidence.

The Government is relying on local authorities to provide more trackers who, like Serco’s, will call up those infected and run through a checklist of questions about who the latter have recently been in contact with.

But how many can be deployed at any one time?  ConservativeHome was told that the tracking effort must avoid “plough waves” – in other words, a surge of calls that could potentially crash the technology being used.

It must be said that the main government systems of the crisis have been well met, with Universal Credit and the furloughing scheme standing up well.

However, Ministers feel that they need to “get this one out slowly”, which will limit the speed of progress.  Then there’s also the question of how many trackers are needed in the first place.

David Davis says between 20,000, very close to the Government’s figure, and 50,000.  Bernard Jenkin calculates 45,000.

Third, there is quarantine. There would be no point in testing, tracking others with whom they’ve been in contact, and then testing them, if all those found to have the virus don’t quarantine.

But the South Korean-type original on which the Government is basing its own scheme applies quarantine very strictly, and the methods used are unlikely to recommend themselves to the privacy-conscious.

These include the use of CCTV footage, credit card transaction data and travel information – not to mention an app on infected peoples’ smartphones sets of an alarm if they leave a designated quarantine area.

Western attitudes to privacy are very different to Korean ones, and much may depend on the degree to which those with the virus observe home quarantine.

Finally, the Government has a big decision to make – if the scheme really gets going in a big way – about whether or not to take the local route to lifting restrictions.

The sources that we spoke to are very cautious.  One described local variety as a “complication”, stressing that “epidemiologists and the NHS people are very wary of complicating the message”.

That would suggest all the ships having to travel at the speed of the slowest in the convoy, so to speak: in other words, areas with lower R rates would have to wait for areas with higher ones to catch up.

Though if “the NHS people” are resistant to a locally-based approach to lifting the lockdown, we can expect the Treasury people to be more positive: the more restraints come off, after all, the better for the economy.

Another day; the same conclusion.  In the absence of a vaccine, this is going to be a long hard slog.