TOMORROW could be the hottest ever July day, according to forecasters.

Temperatures are set to rise once again with the Met Office saying England could see the July record high of 36.7C (98.1F), reached at Heathrow in 2015, broken tomorrow.

Residents are making the most of the heatwave, flocking to parks across Southampton and the nearby beaches.

But several warnings have been issued ahead of Friday with companies urged to let staff work more flexible hours to avoid travelling at rush hour.

Frances O’Grady, general secretary at the Trades Union Congress (TUC), said: “High temperatures mean workers are at risk of dizziness, fainting, heat cramps, loss of concentration and increased tiredness. It’s a good idea to allow flexible working while it’s so hot.

“Many employers already do this all year round, but giving workers the choice of coming in earlier or staying late will let them avoid the sweltering conditions of the rush hour commute.

“The most simple way for staff to keep cool inside when it’s scorching outside is being able to work in more casual clothing. “While shorts and vest tops may not be appropriate for all, nobody should be made to wilt in the heat for the sake of keeping up appearances.”

Meanwhile, Hampshire Fire and Rescue Service (HFRS) is asking the community for help to prevent fires after dozens of firefighters have spent hours battling blazes across the country in the past few weeks.

Steve Ash, group manager for HFRS, said: “We ask the public to do their bit in helping us prevent these fires happening in the first place.

“What this means is taking everything away with you after a picnic or barbecue to ensure nothing is left behind that could start a fire.

“Also make sure you only have a barbecue or light a fire in a designated area and that everything has been properly extinguished before you leave.

“In the unfortunate case of there being a fire we ask that you get to a place of safety and call 999 immediately so we can put it out before it does significant damage to the countryside we all enjoy.”

As previously reported, the number of patients admitted to Southampton General Hospital because of dehydration has increased in the past few weeks, with doctors urging residents to drink three litres of water a day.

Public Health England (PHE) has also issued a new warning ahead of Friday.

Dr Thomas Waite, consultant in health protection at PHE, said: “Temperatures are likely be high in parts of England this week, which may leave older people, young children and those with long-term conditions, including heart and lung diseases, struggling to adapt to the heat. So keep an eye on friends and family who may be at risk.

“To beat the heat, try to keep out the sun from 11am to 3pm, walk in the shade if you can, apply sunscreen and wear a hat if you have to go out in the heat. “Also try to carry water with you when travelling.”

Dr Jason Horsley, pictured, director of public health Southampton City Council and Portsmouth City Council, is also encouraging residents to shut windows and pull down the shades, opening windows when cool enough to do so; have cool baths or showers; drink cold drinks regularly, such as water and diluted fruit juice but avoid excess alcohol, caffeine, including tea and coffee or drinks high in sugar.

Animal charity Blue Cross is asking residents to walk their dogs at the cooler time of the day and make sure dogs have access to clean water at all times. Pet owners have also been urged to avoid exercising their dogs and other animals in the hottest parts of the day due to the risk of burnt paws on scorching pavements, as well as the chance of heatstroke.

The heatwave baking Britain comes as extreme hot weather grips northern Europe.

The all-time UK high is 38.5C (101.3F) set in August 2003.

The UK has seen the driest half of summer on record, with just 47mm (1.85 inches) of rain between June 1 and July 16.

The Met Office said several places have had 54 consecutive dry days, starting on May 30, including a few which have had less than 1mm (0.04in) of rain in the entire 54-day period - the longest spell since 1969, when 70 days passed with no significant rainfall.