For their UK call centre, it says: "0871 246 0000 - 10p per minute." Mysteriously, it also says: "0905 566 0000 - £1.00 per minute." It doesn't specify what the premium line is for, but it says: "Do you have a complaint regarding our premium rate number - click here."
For Sweden, given that's where B747forever is from, they say: "0900 100 0550 - English speaking - 4 SEK per minute." That's about £0.37/minute. Although they do, again, have a premium line: "0900 100 0750 - English speaking - 15 SEK per minute." That's about £1.40/minute.
So, wildly varying prices. If you can get the 10p/minute line if you're in the UK, that's a good price. Perhaps someone could try it to see if they can actually get through.
"Everyone writing for the Telegraph knows that the way to grab eyeballs is with Ryanair and/or sex."