Amber heat health alerts have been extended to cover almost all of England, including the north, as the nation experiences its third heatwave of the year. Temperatures reached 35C (95F) on Thursday, with the alerts now in place until Sunday evening, signalling a significant impact on health services and potential travel disruption.

The current heatwave has already seen the UK break a national record for the most days with temperatures reaching or exceeding 34C in a single year. Thursday's high of 35.5C, recorded in Surrey, marked the eighth such day, surpassing the previous record of seven days set in 1976 and 2020. This figure is expected to increase as the heatwave peaks on Friday.

Rush-hour commuters faced considerable disruption on Thursday evening, with rail operators reporting delays, cancellations, and slower services due to high track temperatures. NHS England has also warned that ambulance services are under sustained pressure as a direct result of the extreme heat. The current heatwave, while not expected to reach the peak temperatures of June's record-breaking event, may prove to be longer-lasting, potentially continuing until the end of next week.

The implications of prolonged high temperatures extend to public health services, transport networks, and energy supply. The extended amber alerts, issued when conditions could put the whole population at risk, underscore the seriousness with which the heatwave is being treated by health authorities. A yellow alert, indicating a possible significant impact, covers the north-east of England.

While the highest temperatures were recorded in south-eastern England, the heat has affected the entire country. Wales saw its highest temperature of 31.3C in Cardiff, Scotland reached 29.3C in Charterhall, and Northern Ireland recorded 27.5C in Killowen. Wimbledon, which experienced record temperatures in 2015, has implemented measures such as providing additional water and electrolytes to players, along with iced towels and umbrellas, and allowing 10-minute breaks between sets if certain heat and humidity thresholds are met.

Transport disruption is a recurring theme during heatwaves. Several train operators, including East Midlands Railway, Great Western Railway, South Western Railway, and London Northwestern Railway, reported service alterations and speed restrictions. Transport for Wales and c2c experienced suspended services and speed restrictions on Friday due to hot tracks, advising passengers to expect delays.

Separately, the UK's electricity grid operator, Neso, issued a request for increased power availability, citing tight electricity margins on Thursday evening. While no immediate risk of shortages or blackouts was suggested, extreme heat can reduce the efficiency of energy processes and increase demand, particularly for cooling.

This record-breaking number of 34C days highlights a potential trend of increasingly frequent and intense heat events in the UK. Experts have previously noted that heatwaves can disproportionately affect certain demographics, with studies indicating that women may be more vulnerable to the health impacts of extreme heat.