July 26 is likely to be the hottest day of the year so far, with 36 °C expected in the southeast, according to the British national weather service.
A similar heatwave in 2003 led to more than 20,000 deaths across Europe, including 15,000 in France alone and 2,193 in Britain.
The lawmakers called on the government to develop a strategy to protect the health of the elderly in periods of extreme heat and social media users took to online platforms to voice their frustration.
The National Health Service has issued tips for coping in hot weather.
The cross-party Environmental Audit Committee urged the government to ensure the NHS is prepared for more frequent heatwaves in the future.