The gates are openpublished at 10:04 British Summer Time 20 June 2017
The turnstiles are turning, the big metal gates have been pulled apart, and Royal Ascot is officially open.
These women are going through at about 100 mph, by the looks of it.
Coverage of day one at Royal Ascot 2017
Barney Roy wins St James's Palace Stakes
Ribchester wins Queen Anne Stakes
Injured Dettori out of Royal Ascot
Armed security increased at racecourse
Adam Whitty, John Hudson and Frank Keogh
The turnstiles are turning, the big metal gates have been pulled apart, and Royal Ascot is officially open.
These women are going through at about 100 mph, by the looks of it.
Adam Whitty
BBC South
Maybe you're a gentleman on your way to Ascot today, or at some point this week, and you're worried about your top hat etiquette.
Or, you're just a fan of all things millinery.
Either way, it might be best to learn the top tips on top hat wearing from a professional hat-maker.
Doug Simpson, from Ascot Top Hats, has been giving us the polite way to manage your headwear over the week, including, how to present it in front of Her Majesty.
A movie script, a Middle East rivalry and an American dream - there are many subplots to Royal Ascot 2017.
Our racing correspondent Cornelius Lysaght has been looking forward to the five-day meeting.
"As usual, the Queen will be holding court during what is acknowledged as her favourite week of the year," he writes.
You can read Cornelius' preview right here.
Tim Dellor
BBC Berkshire sport editor
The big news breaking early today is there will be no Frankie Dettori riding at Royal Ascot this week.
He will be missed, but the show must go on, and what a show. The meeting opens with three Group 1 races.
The first of the 30 races this week is the Queen Anne Stakes at 2:30. Ribchester and Lightning Spear are the two most eye catching runners. They finished 1-2 in the Lockinge at Newbury last month.
Then after the Coventry Stakes for the two-year-olds we've got the King's Stand Stakes. Last year Clive Cox's Profitable won the race. The Lambourn horse might find it tough to defend his crown, though. The American-trained Lady Aurelia is very highly rated.
Today's feature is the St James's Palace Stakes at 4:20. According to the bookies this will be a duel between Churchill and Barney Roy.
Wrapping things up on Day 1 it's the Ascot Stakes, and then the Windsor Castle Stakes at 5:35.
Jockey Frankie Dettori will miss the 2017 Royal Ascot meeting after a fall at Great Yarmouth last week.
Read MoreToby Wadey
BBC South
Royal Ascot will feature more armed officers and security checks following the London and Manchester terror attacks, police have said.
The force said it wanted to reassure the 300,000 racegoers expected to descend on the Berkshire town ahead of the five-day event's Tuesday start.
"Those attending should go about their day as normal," a force spokesman said.
Armed patrols were deployed at Royal Ascot, which the Queen will attend, for the first time in 2016.
The Times
The Times say organisers at Royal Ascot are preparing to relax the formal dress code to combat the effects of the summer heatwave we are having at the moment.
A spokesperson said if it gets too hot, gentlemen will be allowed to remove their jackets.
Top hat and tails are compulsory for those inside the Royal Enclosure.
Ascot looks sublime this morning.
Weather forecasters are predicting scorching temperatures throughout the day, with highs of around 28 degrees (82F).
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Frank Keogh
BBC Sport at Ascot
Jockey Frankie Dettori will miss the 2017 Royal Ascot meeting which starts today.
The 46-year-old Italian had been due for some fancied rides, including favourite Lady Aurelia in the King's Stand Stakes on the opening day.
Dettori, the most successful Royal Ascot jockey currently riding, returned to action at Chantilly on Sunday.
But he was struggling with an arm injury on Tuesday morning and was ruled out of the five-day fixture.
"For me that's soul destroying as it's the most important week of the year," he said.
"I'll be counting the days until next year."
Five days, 30 races, more than £6.5m in prize money - there's high stakes alongside the high fashion at Royal Ascot.
You can hear live commentary of the first four races on BBC Radio 5 live sports extra, with further coverage throughout the day on BBC Radio Berkshire.
Here's the full running order (races in bold on Sports extra). All times BST.
14:30: Queen Anne Stakes (Group 1) one mile
15:05: Coventry Stakes (Group 2) 6f
15:40:King's Stand Stakes (Group 1) 5f
16:20: St James's Palace Stakes (Group 1) one mile
17:00:Ascot Stakes (handicap) 2 1/2m
17:35: Windsor Castle Stakes 5f
Gorgeous manes, perfectly fitting hooves, some thoroughbred stallions and plenty ignoring a stable diet.
And that's just the punters.
Welcome to the most opulent event on the sporting calendar, Royal Ascot 2017.