Royston Wild looks at two FTSE 100 (INDEXFTSE: UKX) income shares that could make you a fortune by retirement. : There’s been no shortage of articles on The Motley Fool UK of late highlighting the perils of just relying on the State Pension to fund your retirement. I don’t know about you, but I couldn’t survive on the paltry £164.35 per week that the current State Pension provides. Heck, many Britons may not even be able to draw on this small sum if their National Insurance contributions don’t match what the government demands.