Weather: Heatwave Health Alert As Mercury Rises With temperatures set to hit a record high for the year, people are being urged to stay safe after a series of tragedies. 6:46pm UK, Wednesday 17 July 2013 Video: 'Enjoy The Sun - But Take Care' Email Health warnings have been issued as Britain continues to swelter in the country's first heatwave for seven years. After five consecutive days basking in 30C-plus temperatures, forecasters said Britain was in the midst of its first prolonged heatwave since 2006. The Met Office responded by issuing a "level three heat health watch" for London and the South East and advised "alertness and readiness" for those in the North West and North East. Level three warnings are only one notch below the most serious alerts and are put out when high temperatures place the very young, the very old and those with chronic diseases at risk. Forecasters said Wednesday could break the record for the warmest day of the year, with temperatures expected to creep as high as 32C (89.7F) in parts of England. No swimming sign Two men have died in Norfolk after seemingly ignoring swimming bans Sky News weather presenter Isobel Lang said: "Wednesday could be the hottest of the current heatwave across the London area with a high of 32C, topping Heathrow's 31.4C on Monday and Kew Gardens' 31.2C yesterday." Referring to the level three heat-health warning for London and the South East, she added: "The temperature threshold for the region is for daytime highs of 31 or 32C (90F) and night minima of 16 to 18C (64F) over two days and the intervening night." The alert comes after a series of tragic accidents in which people have died trying to cool off. Emergency services have reiterated a warning of the dangers of swimming in open water after the bodies of two men were recovered from the water at a beauty spot in Norfolk where swimming is banned. A teenage boy and man in his 40s were found in separate lakes at the Bawsey Pits. There have been four water-related deaths in Wales over the last week. In the latest accident a man in his twenties was reported dead on Wednesday morning after being pulled from the River Ceiriog at Pont-y-Blew, near Wrexham, the previous evening.