Britain has paid record sums to buy electricity from Europe this summer as low river levels force nuclear power stations to power down across the Continent. Experts predict the UK will have to pay high prices again this week as the fifth heatwave of the year hits. German power prices have risen by 25pc to €117 per megawatt hour (MWh), while France and Spain have seen a 35pc rise to around €125 per MWh. Energy consultancy Montel said imported power prices had been "notably more expensive" this summer. Noémie Baud, a UK power market expert at Montel, said: "Overall, year-on-year prices have risen across the board.