Duty : CIF price x 10%
VAT (Value Added Tax) : (CIF price + duty + clearance fee) x 17.5%
Cars under 3 years old : ESVA is required
Cars over 3 years and less than 10 years old : ESVA and MOT
Cars over 10 years old : MOT
Need to change speedometer (to mile), space for the plate etc
About GBP 600
Reference
SVA
http://www.direct.gov.uk/en/Motoring/BuyingAndSellingAVehicle/ImportingAndExportingAVehicle/DG_10018282
http://www.direct.gov.uk/en/Motoring/BuyingAndSellingAVehicle/ImportingAndExportingAVehicle/DG_4022105
MOT
http://www.direct.gov.uk/en/Motoring/OwningAVehicle/Mot/DG_4022514
Other
British Embassy
http://ukinjapan.fco.gov.uk/
Port
Bristol, Liverpool, Southampto