THE outsourced test and trace system for Covid has failed to reach millions of contacts. Currently it misses 40 per cent and yet is going to be boosted by £7bn of funding for what SAGE calls “marginal gains”, whatever that means.

So the Government is now pinning its hopes on the new, quick lateral flow tests to mass test whole populations in Tier 3 regions as well as students returning home for the holidays.

This will come at a further cost in excess of £43bn, if not the £100bn the Prime Minister announced. But this is a screening programme. The NHS National Screening Committee should have assessed its benefits and risks before giving approval. They didn’t.

The Government says that the new tests are sensitive and accurate enough to be used in the community. But are they?

An analysis by Public Health England Porton Down and Oxford University suggests not. A high rate of false negatives is generated and accuracy depends upon who does the test.

If it is a healthcare worker, 27 per cent give false negatives but self-testing provides 42 per cent false negatives.

So a significant number of students who tested themselves negative twice would be virus carriers and possible spreaders.

And not all positives are positive either. This is reinforced by biostatistics professor Jon Deeks, of Birmingham university, who describes as an example that out of a population of 100,000 people where 400 are infected the test would show 630 infections but with just 230 of those actually positive. That means it misses 170 true positives and labels 400 people as positive when they are not!

So, unsuitable for a safe test and release of people from lockdown measures or students from university as claimed by the government.

What next I wonder?

D Duell, Durham.