Hell yes you claim back the difference between what your employer pays you for your mileage & the 40p . This is also taxable . You get tax relief @ 22% if you dont pay 40% tax . Ive got 19000 biz miles to claim alrady this year with 4 moths to go. I claimed 6000 last year & got a £576 rebate. Phone centre 1 ask for an exspensizes claim form.