Shrouded in secrecy, guarded by guns. Today, we're taking you inside one of the most mysterious institutions in the country.

Microorganisms in the chemicals that we have are here, or probably the most dangerous substances known to man.

The Times has been granted rare access through the airtight doors at Porton Down.

The Ministry of Defence laboratories where they research chemical weapons and killer diseases.

It's a timely tour, as in an exclusive interview, the Defence Secretary has issued a stark warning.

The Times carries an interview with the Defence Secretary who is warning of a growing threat of chemical and biological attacks.

We've seen plots exposed in Europe. It is, unfortunately, what happens in a sort of breakdown of world order.

Do you have enough space in your mind to deal with another horror story?

You're listening to stories of our Times from the Times and the Sunday Times. I'm Manvin Rana. Today, inside Porton Down.

Deep in the Wiltshire countryside sits a 7,000-acre plot of some of the most closely guarded land in Britain.

The Defence, Science and Technology Laboratory at Porton Down.

It looks a bit like an ordinary out of town industrial estate, only with rows of barbed wire outside and police officers carrying guns.

And not just any old guns, the thought that we used by the Navy SEALs to kill a sarmor bin Laden.

So what goes on here behind the barbed wire fences?

And what of the scientists who work here learned about the threats facing the country?

I spoke to our newest colleague.

Would you mind just starting by introducing yourself?

Yes, I am Larissa Brown and I am the Defence Editor for the Times.

Well, Larissa, we're firstly welcome.

Thank you.

Is this your first day?

It is, which is quite a busy day.

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