Revellers have been soaking up the sunshine at what is thought to be the hottest ever Notting Hill Carnival.

The streets along the route in west London were awash with colour as hundreds of thousands of partygoers enjoyed the beginning of the long-standing celebration of Caribbean heritage in the capital.

About one million people are expected to flock to west London on Sunday and bank holiday Monday for the carnival, which has been running for more than 50 years.

Revellers soak up the sun at the annual street party. Credit: Victoria Jones/PA
Almost a million people are set to attend the carnival over two days. Credit: PA

Organisers have described it as the UK’s “biggest celebration of culture, diversity and inclusivity”, and promised this year’s will “once again be full of vibrant colours, incredible music and dancing”.

Record-breaking temperatures were recorded at Heathrow, the thermometer hit 31.6C, breaking the previous record of 31.5C, 18 years ago in 2001.

Meteorologist Steven Keates said said: “It’s looking like this is one of the hottest carnivals ever.

“Tomorrow looks like it’s going to be hot again, so I would urge people to stay safe in the sun, drink plenty of water and enjoy themselves.”

The streets along the route in west London were awash with colour. Credit: Victoria Jones/PA
The party atmosphere was in full swing at the UK's largest street party. Credit: PA

While the dates of carnival were not fixed in the early days, it has been held on the late August bank holiday weekend for at least four decades, organisers said.

Onlookers gathered on pavements in the sunshine as the community celebration began carving its way around west London in a mass of music, dancing and bold costumes of neon Lycra and brightly-coloured feathered headdresses on Sunday morning.

As with last year, a silence of 72 seconds was due to be held on both days in memory of those killed in the Grenfell Tower fire in 2017.

The tower block is within half a mile of the parade route.

The crowds enjoyed ice-creams and clutched water bottles as they meandered through the streets to the beat of steel pan drums, as well as dance hall music blasting from speakers piled on to floats.

Almost 12,500 police officers and some 1,000 stewards will be in place across the two-day event to ensure a “safe and spectacular” festival.

After what Metropolitan Police hailed as a successful use of screening arches – used to detect offensive weapons – for the first time at the carnival in 2018, there are “significantly more” dotted around the area this year.

A young dancer performs during the Children’s Day parade Credit: Victoria Jones/PA

Scotland Yard has not said how many arches are being used or where they would all be positioned, but described them as a “fantastic deterrent”.

The force, which has had to respond to a spate of stabbings across the capital in recent years, admitted last year that not everyone attending the event would pass through the screening facilities.

In 2018 there were two non life-threatening stabbings over the carnival weekend and some 45 police officers were injured.

The force said it will be “taking every step to make sure that doesn’t happen this year”.

On Sunday people, including families with buggies, walked through six arches placed on Westbourne Grove which were flanked by police officers.

Carnivalgoers have been advised to be prepared for very hot weather by taking water or refillable bottles and downloading the official carnival app to keep up to date with the location of medical points and food stops, and to get updates on transport delays.