In association with BBC Panorama, we investigate the world of tax havens and show how some of the world’s most famous companies are using a tax haven at the heart of Europe to save millions in tax. Secret documents reveals how companies like GlaxoSmithKline have been getting big tax breaks on billion pound transactions in the tiny country of Luxembourg. By opening offices there, diverting profits overseas and then having their Luxembourg office lend offices in other country money, they can avoid multi-million euro tax bills in their country of origins. In these austere times, is big business paying its fair share?