Duty payable (UK)
In the UK the government have recently introduced a new tax incentive for vegetable oil based fuels. The definition of biodiesel is 'an ester of vegetable oil fatty acid', which includes methyl ester (biodiesel made with methanol) and ethyl ester etc. Also, from a technical perspective, vegetable oil in it's pure form is an ester, therefore it should also come under the tax ruling, but customs and excise consider that because it is not 'diesel quality' it is not elligible for the reduced tax rate. The duty payable on biodiesel is now 28.35 pence per litre (+ VAT), as opposed to 48.35 pence for ultra low sulphur diesel (September 2006). The duty payable on vegetable oil, or SVO, is 48.35 pence. Duty does change regularly, so these figures are not always up to date. More recently, customs have given a ZERO tax rate payable on biodiesel and vegetable oil, if production is less than 2,500 litres per year.
It is taxed, and you should account for the duty payable to HMRC...if you produce more than 2,500 litres per year. Unlikely LOL so looks like you're OK.