You can buy a subscription for a UK number through Skype. For a time, I had a US and a UK number on there, and just chose which number to phone from when using Skype for actual phone calls. Now, I maintain the US-based one, mostly for doing business with US clients, but also as a number attached to the bank account I still have in the US. There's voicemail, so people can leave you messages and won't know you're not actually based in the UK.