How long can a 99 ice cream last in this year's heatwave? The popular summer treat was put to the test in central London.
– Boris Johnson, Mayor of London
Obviously this is a serious issue for us. The advice as everybody knows travelling on the tube on a very hot day is do take water with you.
If you are feeling faint, if you're feeling suddenly you're going to be taken ill, don't wait to faint on the tube, get off on to the station platform or concourse where someone will look after you.
– Network Rail
On hot days, rails in direct sunshine can be as much as 20 degrees centigrade above air temperature.
As rails are made out of steel, they expand as they heat, and that expansion has to be managed. If a section of track is judged to be at risk, we introduce local speed restrictions to reduce the risk of track buckling.
Our teams know the areas at risk and we have watchmen in place today and tomorrow to keep an eye on them. Areas of concern can also have their rails painted white to reflect the heat.
- Network Rail is warning track temperatures could be 20 degrees higher than air temperatures, raising fears of buckling
- Teams of "watchmen" will be monitoring potential hotspots and may impose temporary speed limits where tracks reach 50C
Rail bosses could be forced to introduce speed restrictions on some train services in London because of the heatwave.
Temperatures in Central London could hit 30C this afternoon, making it the hottest day of the year. Tomorrow will be even warmer.
Parts of London have been warned to brace themselves for potentially dangerous levels of heat amid predictions that temperatures in the capital could be warmer than Hawaii and The Bahamas.
Health officials issued a heatwave alert following forecasts that temperatures may reach 32C (90F) in London on Friday.
Current figures suggest the hottest spots in London also look set to be warmer than European holiday resorts such as Crete (30C) and Ibiza (29C).
With temperatures set to soar, Public Health England (PHE) said that heatwave conditions can have a "significant effect on health".
- The exceptionally hot conditions are expected to start on Thursday evening and continue to Saturday.
- Public Health England says people should consider staying out of the sun during the hottest part of the day, to drink plenty of fluids and wear sun cream that is at least factor 15.
- It has also asked people to be aware of children and the elderly, to ensure they are not suffering because of the heat.
Public Health England has warned this week's heatwave in the South East could have a "significant effect on health".
The Met Office has declared a level 2 heat-health alert. It's activated when there is at least a 60% chance of temperatures being high enough on at least two consecutive days and into the night to have a impact on health.