On Times radio today discussing the Goverment's new mass testing plans using lateral flow tests for millions with the slogan 'are you ready, get testing, go!'.I hope the reporting is inaccurate, because such a campaign is potentially disastrous. Here's why:

Lateral flow is an excellent form of 'red light' testing. If you come up positive, you have the infection even if you feel fine. So mass testing can pick up asymptomatic cases and ask them to self-isolate in order to break chains of transmission.

Of course, this depends upon people being able to self-isolate, so testing without support for self-isolation is yet another half-baked approach which focusses on one part of the system and ignores the others that are necessary for it to work.

On the other hand, lateral flow is poor as 'green light' testing. There are many false negatives when the test fails to register the virus even though it is there. So a negative test doesn't tell you that you are fine to go.

Indeed if tests lead people to relax their guard, mix more and forget safeguards then they can actually be counter-productive, increasing rather than decreasing the overall level of infection. That is why so many have warned against careless roll out of lateral flow testing.

So, whether you get the advantages (spotting asymptomatic cases) or the disadvantages is very dependent on the messages and explaining why and how the tests are being used - in particular, warning against complacency.

And a slogan like 'are you ready, get testing, go' is just about the worst message you could give, encouraging the belief that these tests are a green light to get out and go rather than a red light to self-isolate - when the reality is precisely the opposite

So, an urgent appeal to the Government: please please reconsider your messaging on this campaign. It is a disastrous error.