Just had a quick read of the VAT margin scheme, and it only appears to apply to a few select cases, second hand items being one of them.
I believe the case being made by Clive implies a new item being resold as new by the vendor, in which case the second hand argument does not hold true and the VAT margin scheme cannot be used – otherwise every purchase of items used for resale could be argued to be second hand and therefore subject to the margin VAT of 16.67%.
I had a similar issue a few years back where I was looking to re-sell items made by a colleague of mine. I was VAT registered, he was not, I could not make any profit on selling the item for the same price as him, even with the low price that he was selling items in bulk at to me, purely because I had to add VAT to all items that I sold, whereas he did not.
A couple of years ago I worked out that for £2.00 of gross salary spent on petrol, £1.80 goes to the government as Income Tax, NI, VAT, duty, etc, £0.20 was the actual cost of the petrol (varied slightly dependant on the individual's tax band) – I am sure things have become much worse since then.