London Heathrow, the largest freight airport in the UK, remains the most expensive industrial location in Europe for occupiers, with prime off-airport rents now at EUR 238 m[sup]2[/sup] per year, according to King Sturge's Airport Property Market survey for 2008. Improved economic and occupier outlook across Europe, combined with a shortage of available prime space in metropolitan areas are driving up out-of-town office rental values, the property adviser says.