The distance from Malaga to London is approximately 1000 miles. The best way you can get is to fly, an average of 3 flights per week with a trip duration of 3 hours. Flying to London from Malaga is cheapest via Ryanair (£50), British Airways (£80), and EasyJet (£95).
If you're looking for an option to get to London City Airport apart from the flight, opt for bus and train via Zaragoza, which takes around 35 hours and costs €200 - €350.