Wednesday was the hottest day recorded in the first half of April since 1946, the Met Office said.

Temperatures reached a high of 26.6C in Kew Gardens, south west London, the forecaster said.

The record temperature is the highest recorded in the United Kingdom during the first half of April in the last 80 years.

It comfortably surpassed this year’s previous warmest day, recorded on Tuesday, when temperatures hit 24.8C in Mona, on the island of Anglesey in Wales.

London was also hotter than popular holiday destinations, including Ibiza, Rome and Marrakech.

Tom Morgan, a meteorologist at the Met Office, said: ‘Temperatures even into the mid 20s are very uncommon at this time of year.

‘In the London area, we’ve seen temperatures above 26 degrees Celsius, and currently the provisional maximum today is 26.6 Celsius in Kew Gardens, London. And that is pretty exceptional for at least the first half of April. 

‘It’s been very, very warm, but it is a brief peak in the heat, with temperatures for most of the UK considerably lower tomorrow.’

Wednesday was the hottest day recorded in the first half of April since 1946, the Met Office said. Pictured: People sitting in St James Park, London 

Temperatures reached a high of 26.6C in Kew Gardens, south west London

A young couple kiss while sitting on the seawall in the sun in Westcliff on Sea

Forecasters have also warned of a ‘pollen bomb’, as levels soar across much of the country.

The hot spell, which began on Monday, is far above the early April average of 12C to 15C.

But not all areas of the country have been lucky enough to enjoy a share of the sunshine. 

Conditions were cloudier and cooler across Northern Ireland and northwest Scotland on Wednesday, with outbreaks of rain at times.  

Forecaster Mr Gundersen confirmed the warmth of the last few days may unfortunately be ‘short-lived’ for some parts of the UK. 

Thursday is expected to see rain and cooler, showery weather moving southeast across the UK.

As people flocked to the coast in the warm weather, a charity urged people to make sure they stay safe when cooling off.

Water safety charity the Royal Life Saving Society UK said that research had found the risk of accidental drowning increased fivefold during warm weather.

A spokesperson for the charity said: ‘Although air temperatures are warm, water temperatures remain very cold. The shock of cold water can make swimming difficult and increase the difficulty in getting out of the water.’

Britons flood to the coast in Lyme Regis to make the most of the hot weather on Wednesday 

The seafront in Lyme Regis busy with holidaymakers on Wednesday 

Holidaymakers pack out the beach at Lyme Regis on Wednesday 

Two young boys have died in bodies of water in recent days.

In Cumbria, a body was recovered by police on Tuesday after a 17-year-old boy went missing at High Dam Tarn.

And on Monday, a seven-year-old boy died in hospital after emergency services responded to reports of a child in trouble in a small pond at a golf centre in March, Cambridgeshire.

A spokesperson for the drowning prevention charity said: ‘Stop and think before getting into water and always stay together. In an emergency, call 999 immediately. Stay out of the water yourself. 

‘Tell them to keep calm and throw something that floats, such as a plastic bottle or football, for them to hold onto and stay afloat while help is on the way.’

Despite the high temperatures, the Met Office has said that this week’s weather does not meet its definition of a heatwave, which requires temperatures to exceed region-specific thresholds of 24C and 27C for at least three consecutive days.

The hot weather has also coincided with peak pollen season in the UK, with ash and birch pollen levels remaining ‘very high’ according to the Met Office.