24/07/2012 05:24 BST | Updated 24/07/2012 06:04 BST

Danny Boyle Urges London 2012 Opening Ceremony Rehearsal To #savethesurprise (PICTURES)

The first time London hosted an Olympic opening ceremony – in 1908 – organisers probably had an easier job keeping the details secret.

But in 2012, stopping a dress rehearsal audience of tens of thousands, almost all with camera phones, video cameras, Facebook and Twitter, from letting slip the secrets of Danny Boyle’s London Olympics opening ceremony, would be a feat of Olympian proportions.

At the technical rehearsal of the ceremony on Monday night, Slumdog Millionaire director Mr Boyle pleaded with the crowd to keep the details a secret – asking them tweet #savethesurprise.

A Twitter user posted a picture of the London 2012 Olympic opening ceremony set at the technical rehearsal

At a press conference showing a mock-up of the set, the director admitted to journalists that "part of the modern world means you can't really do that.”

The hashtag was emblazoned on huge billboards in the stadium, and many of those tweeting at the ceremony posted photos of the scenes – with their hands in front of the camera. And those who did post pictures were attacked and berated by others on the social networking site.

Many tweeted cheeky clues to what might be expected when the Olympics opens on Friday evening:

And some took the opportunity to start rumours about the content:

So has guilt worked to keep details of the ceremony from leaking?

Organisers have revealed that the ceremony's theme is 'Isles of Wonder,' inspired by William Shakespeare's 'The Tempest'.

Kenneth Branagh is rumoured to be reciting a speech by Caliban from the play, replacing Mark Rylance, who pulled out after the death of his stepdaughter. Muhammed Ali and David Beckham are also rumoured to be taking part in the ceremony, having both flown into London this week.

A pre-recorded film, involving the Queen and Daniel Craig as James Bond, is reported to have been filmed inside Buckingham Palace, and a stuntman dress as 007 is to parachute into the stadium.

The show will also depict the dark side to William Blake’s poem 'Jerusalem'.

As well as the “green and pleasant land”, the ceremony will have the “dark satanic mills” –including unemployed protesters from the Depression, miners and factory workers.

Other parts will celebrate great British institutions like the NHS, with nurses performing a tribute to the health service. Songs heard blaring from the stadium range from The Beatles and the Sex Pistols to Dizzee Rascal and Tinie Tempah and the theme tunes of the Archers and Dr Who.

The Sunday Times also reported that one section will feature a showdown between J K Rowling’s Harry Potter villain Lord Voldemort, and a flock of flying 'Mary Poppins' nannies.

One secret is still closely guarded: the identity of who will light the Olympic flame.