Delving deep How we compiled the data
The Telegraph tracked online flight prices between June 24 and July 9 from any London airport to common destinations, using the cheapest economy option for two adult passengers for equivalent periods in July and September. Data for our basket analysis was calculated from prices listed on PriceSpy, a website that logs the costs of a wide range of goods offered by retailers in Britain. To build our baskets, we first organised individual products into broader categories – e.g. painkillers, blenders or drills – and in turn placed these into baskets that represented different areas of life. We then selected a sample of products for each category and created a comparison only using those products with prices available at the beginning of the year.