The Met Office said high pressure had allowed exceptional heat to build across the UK, with temperatures expected to remain in the high 20s and low 30s for much of the week.
Dr Anya Gopfert, consultant in health protection at UKHSA, said even moderate heat could lead to health problems for older people and those with health conditions, urging everyone to take “simple precautions”.
A Met Office study has also found climate change has made breaking May temperature records around three times more likely.
It said what was once a one-in-100 year event is now a one-in-33 year occurrence, with average May temperatures rising over recent decades.
