Fascinating.

There is a bright forward leaning "S" towards the top of the UK. Working from the bottom are the big conurbations (west to east) of Liverpool, Manchester, Leeds working up the coast through the North East, past Newcastle and on to Edinburgh and Glasgow, the last part of the "S" goes up to Aberdeen (I think) before fading out into the North of Scotland. It makes me realise why the Scottish Highlands are such a lovely holiday destination - you really can see the sky from there.