By Angus Stickler
I started my search with a computer and the help of London University student Nigel Eady.
Nigel entered in the words 'sarin' and 'synthesis' to a basic search engine and immediately came up with a long list of links to information about sarin.
The chemicals Angus Stickler bought are being stored carefully
We click on the first one which takes us to a website for Bristol University, where, on its first page there is a description of the various stages of making the compound.
With just three clicks, we've found a recipe for making sarin in five easy steps with four chemicals.
I phoned Bristol University which has removed the link from its website.
Armed with the recipe, I go in search of the ingredients.
First, Derbyshire-based chemical company Fluorochem.
All I had to do was give my credit card details and delivery address over the phone.
A box covered in orange toxic stickers arrived a couple of days later.
Swallow just 4g of this chemical and you're dead. They sold me 250g.
To be fair the managing director of Fluorochem did ask me what I wanted it for.
I told him it was for research into the chemicals used in pesticide manufacture.
He told me there was a problem - I wanted 500ml - the smallest quantity they could provide was two and a half litres. It needed special delivery and that was expensive.
The company also wanted the order faxed through on headed note paper. He helpfully he told me what I should write.
We believe this thorny area is the responsibility of government agencies, whose role is specifically to protect the community from potential misuse and abuse
A quick cut and paste to make up the fake BBC headed note paper, and I composed the letter.
"Dear Mr Birch,
Further to our conversation earlier, I would like to confirm the order.
I recognise that this is hazardous material, and give an assurance that it will be handled and disposed of properly in accordance with COSHH procedures."
The chemical was delivered within a week.
I pressed on and phoned through the orders for the last two chemicals. In total, a complete shopping list for Sarin.
Fluorochem could only provide me with one of the chemicals, but I had found it elsewhere by then anyway.
Again all I needed was my credit card and the fake letterhead to Molekula based in Dorset.
At no point did either of these companies check my credentials.
With a modicum of deception I was able to buy the precursors of a chemical weapon - a weapon of mass destruction.
Neither company has done anything improper. Both issued us with statements.
Fluorochem said: "The Home Office has confirmed that none of the products supplied to you requires a licence.
"We fully comply with Home Office Guidelines on restricted chemicals. We conduct ourselves properly and professionally in these matters. We understand clearly the point your programme is making and in many ways welcome it."
And Molekula said: "Molekula makes every effort to screen all orders from individuals for all products which are considered to be of a sensitive nature. We only ship material to company addresses and do not supply to private residences.
"On the wider subject of chemicals with potential double use, we believe this thorny area is the responsibility of government agencies, whose role is specifically to protect the community from potential misuse and abuse."
The name of the BBC gave me some credibility. But the corporation is not generally associated with chemical research. There are no laboratories here.
I used a credit card to buy the chemicals, not a company order form - even the headed notepaper was doctored. If security checks were made, they failed.
The chemicals are now in my possession, locked away in a safety cabinet.
All a potential terrorist would need now, is the where-with-all to make the stuff. And you don't need to be a professor to work it out.
Our student Nigel Eady took me to his university's lab.
He has an extractor fan, glass beakers and some condensing and cooling equipment.
"Standard chemical equipment which you could find in any school, " said Nigel.
"It's not really a high tech operation, or greatly technical knowledge that you need, or even complex apparatus to produce a compound like sarin."
He said you could even make it in a well-ventilated garage.
We bought enough of these chemical precursors to make twice the amount of sarin used in the Tokyo subway attack.
The delivery method is tried, tested and easily improved upon.
The tube trains acting as pistons would force this home-made gas throughout the underground. Tens of thousands could be injured or die.
The only difference between the chemical used in Tokyo, or Iraq by Saddam Hussein, is that this time it could be bought, built and used in Britain.