The cost of living varies dramatically across the UK, with housing, food, fuel and other essentials all costing different amounts in different regions. SilverDoor Apartments has produced figures for how much money you need each month per household to have a comfortable life, where your rent or mortage repayment only takes just over a third of your earnings. We look at these figures in the most expensive and cheapest towns and cities around the nation, and what's behind the huge differences.