The recent warm weather of late is set to continue this week, with temperatures on the rise and Lancashire is expected to see highs of around 27C towards the end of the week.
Temperatures could soar to more than 34C in some parts of the country on Wednesday, beating the 33C recorded at Porthmadog in North Wales on June 28.
Forecasters said there is a chance of hitting 34C or 35C, which could put Britons in line for the hottest day since the mercury hit 34.5C at Heathrow on June 21 last year.
The hottest July day on record is 36.7C (98F), which was reached at Heathrow on July 1 2015.
Nearly all parts of the UK are seeing above average temperatures, but it will be hot or very hot towards the east or south east.
Met Office forecaster Alex Burkill said: "It does look likely it will be at least 33C at some point this week, most likely on Wednesday or Thursday, in the south east and east, London, Essex, Kent, east Anglia and into Lincolnshire - and that would make it the hottest day we have had so far."
Although temperatures are likely to be lower elsewhere, they are still set to be scorching, with Lancashire expecting to reach highs of 27C on Thursday (July 26), with pure sunshine throughout the day.
This hot weather is then expected to trigger thunderstorms throughout various parts of the UK towards the end of this week.
Mr Burkhill added: "The heat and humidity means there is a lot of energy in the air and a high risk of intense thunderstorms. Whether or not it will happen is where the uncertainty is."
Cloud and rain, possibly heavy and thundery, is currently forecast to arrive in the region on Friday, accompanied by temperatures of around 24C.
During the current heatwave, UK temperatures have been approximately 10C higher than average for this time of year.
Lancashire can usually expect highs of around 19C and lows of 13C during July, therefore this Thursday’s peak of around 27C is well above average.
Mr Burkill also explains how the current run of fine weather looks set to continue, stating: "It always seems that when the schools break up that is when we get the bad weather, but in this instance that is not the case."
Warm temperatures are expected to continue well into August, with Lancashire set to see sunny, dry and warm days throughout the summer holidays.