Pheonix reclinata
Ok so we couldn't resist putting this one in, even though you'd be lucky to find a plant, and even luckier to grow it outside in the UK, but both are just possible, maybe. What a beautiful plant this is; the archetypal watering hole palm looking as though it should have a camel tethered to its trunk - except that this one is growing in the middle of a busy roundabout in Rome. It is a part of the date palm family and as consolation we can grow its close relative the Canary Island Date Palm quite reliably in the UK.