you don't if you are solely doing recovery work.. but you do if you doing vehicle transportation I.E dealer transfer's things like that.. a spec lift cannot be used for carrying anything else only cars or bikes therefore if just for roadside recovery it is mot exempt, because it is then classed as an emergency service vehicle and you get road tax at a lower rate. my 7.5tonne renault midlum crew cab recovery truck was 165 quid a year.