With all the confusion around company car tax could you clarify the tax allowance for emergency services lease cars for those of us who respond to incidents. As a fire officer I respond in a lease car which is fitted with blue lights etc. The vehicle is also used for private use when not on duty. My understanding is that less tax is paid because of this which I'm afraid is a grey area to me.

My recent P11D showed figures of Annual value plus expenses - £5252, Amount made good or from which tax deducted - £4143, cash equivalent £1109.

These figures are never properly explained by the issuer so I was hoping you may be able to tell me what they actually mean and how much extra tax as a 40% tax payer I am likely to pay a month.