Hello and welcome to more or less on the BBC World Service with a programme that takes a deeper look at some of the numbers making the headlines and I'm Tim Hafen.

This week on the programme we speak to Professor Martin Landre of Oxford University.

Professor Landre and his team established the Recovery Trial, a large clinical trial on across the UK that searched for effective therapies for Covid by rethinking the way the National Health Service in the UK gathers data.

Recovery has been praised across the world for its discovery of the game-changing Covid treatment dexamethasone, which has saved an estimated one million lives globally.

For Martin Landre hopes that's just the start of what a trial platform such as Recovery can do. He started by telling me how the Recovery Trial was born last year with a threat of coronavirus rapidly bearing down on the UK.

This started with a bus journey in which I happened to be stood next to Jeremy Farrah, the Director of the World Conscious.

We were chatting about the horrendous situation and horrendous stories which were emerging out of Northern Italy at the time of running out of intensive care beds, having to turn people's ventilators off early simply so that the ventilator could be given to other people with a better chance and so on.

Truly horrendous stories and it became clear to us as we were talking that number one the pandemic was coming to the UK at scale and it was likely to do so within two weeks or so.

At some point soon people are going to start thinking about treatments and if we're not careful the drugs will get phone patients in the hope that they work but without any knowledge and without any chance of actually finding out.

And it was exactly in this time that one would really want to see good evidence from randomised trials at the point at which patients are going into hospital.

We had to get it so that the trial was in fact part of standard NHS if you like clinical pathways, clinical pathways in hospital are the sort of processes the maps if you like about who sees which sorts of patients first, what tests they get, what treatments they get, which more so to and so on.

And we had to make sure that this trial was part of that clinical pathway.

One of the recovery trials most notable successes was its investigation into the effectiveness of the drug hydroxychloroquine which was heavily pushed by former president Donald Trump at the beginning of the pandemic as a potential miracle treatment.

Many doctors think it is extremely successful, the hydroxychloroquine. I happen to believe in it, I would take it as you know I took it for a 14 day period and I'm here.

I'm here, right? I'm here. I happen to think it works in the early stages.

I'm imagining a patient comes in the very ill, having trouble breathing looks like they're going to have to go into intensive care and I hear from various experts that hydroxychloroquine might be effective.

So as a doctor, I give the patient hydroxychloroquine and hopefully they get better and if they get better then the hydroxychloroquine worked.

What's wrong with that view of prescribing drugs? You know the expert recommended it, give it to the patient, cross your fingers and if the patient gets better the drug worked.

So let's start and pick that a little bit. The expert gave you the advice. I mean you have to question on what basis were they an expert?

What information did they have that gave them good grounds for believing this hydroxychloroquine drug, which is a treatment for malaria was going to work on a viral infection.

And we know lots about hydroxychloroquine because it is very widely used in malaria. But this is a new virus and there's no sound reason for knowing that it would work in these circumstances.

Second thing, you suggested that if your patient was to get better, you'd know the hydroxychloroquine worked. You wouldn't know that at all. You'd simply know that they took hydroxychloroquine and they got better.

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