The Queen has sounded the klaxon for the start of the London marathon as 40,000 runners pound the streets of the capital in sweltering conditions.
The 38th edition of the world-famous race may well be the hottest on record, with highs of 23C expected throughout the day.
Runners have been advised to drop their goal-times because of the hot weather and organisers have added more ice, water and run-through shower stations along the race course.
The Queen has sounded the buzzer from Windsor Castle for the beginning of the London marathon
The Queen chats to Sir John Spurling, ahead of the London Marathon, which will see 40,000 runners on the 26.2 miles to The Mall
The race started when the Queen pushed the button in front of the Round Tower in the grounds of Windsor Castle
The Queen smiles as she arrives for the start the London Marathon from Windsor Castle this morning
Journalist Bryony Gordon and plus size model Jada Sezer are running the London marathon in their underwear today
Competitors from the Great British Bake Off smile for the cameras before the start of the annual event
Among this year’s runners are firefighters who tackled the Grenfell Tower blaze, a police officer stabbed in the London Bridge terror attack and members of the Stephen Lawrence Charitable Trust.
The 18-year-old – who was a keen runner – was stabbed by thugs at a bus stop in Eltham, South East London, 25 years ago today.
Journalist Bryony Gordon and plus-size model Jada Sezer are making their way round the 26.2 mile course in nothing but bras, knickers, socks and trainers.
The brave pair are running to raise money for Heads Together, the mental health charity set up by the Duke and Duchess of Cambridge and Prince Harry.
They are also hoping to encourage other curvy women to embrace exercise.
Among this year’s runners are members of the Stephen Lawrence Charitable Trust, including his mother Doreen (centre)
Runners arrive for the start of the race which is expected to be the hottest ever London marathon
The brass band play at the beginning of the London marathon which will see 40,000 runners pounding the streets of London
Hundreds of police officers are on duty to keep around 800,000 spectators and runners safe.
Competitors started in Blackheath, south east London, running a snaking route along both sides of the Thames, finishing on The Mall near Buckingham Palace.
Last year, the event raised £61.5 million for charity, a world record for an annual one-day fundraising event, making the total raised since 1981 around £890 million, organisers said.
Among this year’s runners are the heroic firefighters who tackled the Grenfell Tower blaze in June
A record 386,050 people applied for this year’s race – almost a third more than last year and the highest number for any marathon in the world.
Britain’s David Weir won the men’s wheelchair race at the London Marathon for the eighth time after a thrilling sprint finish.
The 38-year-old pipped Switzerland’s Marcel Hug into second place, with Daniel Romanchuk of the USA third.
Temperatures today are expected to beat the race’s 1996 record of 22.7C.
The previous warmest races in the capital were in 1996 and 2007, when highs of 22.2C were recorded.
Fun runners prepare their fancy dress ahead of the annual race that will see 40,000 runners through the capital