Ben Cowell from the National Trust has tweeted, external a picture of the Magna Carta Memorial rededication.

Image source, National Trust

The trust owns the Runnymede site which has been dubbed the "birthplace of modern democracy".

Living in Britain today, it's hard to imagine a time when nearly all of us had no say in how the country was run, or how our rulers governed us. That time was 800 years ago.

Before then, kings could do pretty much whatever they wanted. And they did.

But in the year 1215 their authority was challenged. The resulting agreement was called Magna Carta and changed the relationship between ruler and ruled forever.

Today, we can all challenge authority and digital technology gives us more opportunity to do that than ever before.

BBC iWonder looks at the power of the technology you can fit into your pocket.

The Queen and the Duke of Edinburgh were joined by the Archbishop of Canterbury Justin Welby and Prime Minister David Cameron at Runnymede earlier.

Image source, PA

It all happened on the same spot where King John accepted the historic document that limited the power of the Crown in 1215.

One of the high profile moments from today's ceremony was David Cameron's speech.

Image source, PA

He talked about British pride in Magna Carta and how its principles are held dear by many.

Nicholas Davies has tweeted, external: "So thankful to be living in a country where the Government is not above the law.

"Many happy returns #MagnaCarta"

The audience are on their feet as the Queen walks across the stage to unveil a plaque.

She is now meeting people who are at the ceremony today.

We'll bring you pictures of the Queen as soon as we get them.

David Cameron says Magna Carta is something every person in Britain should be proud of.

He says its principles shine as brightly as ever.

"We hold these things dear and we should hold them even dearer for the fact they took shape here on the banks of the Thames."

You can also see a short video of part of his speech here, external.

Prime Minister David Cameron is speaking at the celebrations.

"What happened in these meadows 800 years ago is as relevant today as it was then.

"All over the world people are still struggling to live by the rule of law."

The Union flag is displayed alongside the US stars and stripes on the memorial today.

Image source, PA

Magna Carta has huge significance to a lot of Americans. Find out why here.

Mark Carter
BBC Surrey

A hush has fallen over the meadow ahead of speeches by the Master of the Rolls and Prime Minister David Cameron.

More than 4,000 people have gathered in Runnymede for today's ceremony.

David Starkey is at the event. "It's the kind of thing we Brits do so well," he says. "The whole thing is saying something important did happen and it's worth commemorating it."

He said the Queen, who had just arrived at Runnymede, had followed the expect route from Windsor taken by King John in 1215.

"I hope the Queen is in a better temper than King John would have been here 800 years ago. King John comes here dragged, furious, reluctant."

Today's Google doodle is an animation about Magna Carta.

Image source, Google

It shows a line-up of barons with King John putting his stamp on Magna Carta after the deal is struck.

Hew Locke's new artwork is not to everyone's liking.

Alistair Pike has tweeted, external: "Putting out 12 chairs without a table isn't a #sculpture #MagnaCarta #BBCNews #art #chairs"

But tell us what you think. You can tweet us @BBCSurrey, external or email us.

Adrian Harms
BBC Surrey

Events are taking place all over the meadow.

Here's a parade of flags by school children from Surrey - you can also see the video here, external.

Adrian Harms
BBC Surrey

The Duke of Cambridge has unveiled The Jurors art installation at Runnymede.

See video, external of the artwork's official moment.

More people quoting Tony Hancock on Magna Carta in these links tweeted, external by Joshua Rozenberg.

He writes: "The real meaning of Magna Carta. By @JackofKent jackofkent.com/2015/06/the-me…, external And by me (written last year) with video: bl.uk/magna-carta/ar…, external"

We are are not the only ones covering the events in Runnymede.

Get Surrey, external is providing live updates from the ceremony and performances too.

Hew Locke's art installation has now been officially unveiled.

BBC Surrey presenter James Cannon caught up with the the artist a short while ago.

The chairs include a representation of the key to Nelson Mandela's jail cell door.

Adrian Harms
BBC Surrey

Prince William has arrived - with a crew of photographers behind him.

For the royal party, The Duke of Edinburgh, the Duke of Cambridge, Princess Anne and her husband Vice Admiral Sir Tim Laurence will be at the event.

Jack Fiehn
BBC Surrey Political Reporter

Children are performing something called the Freedom Game on the meadow.

It's based on Magna Carta themes of human rights.