Crowds told to keep quiet at Olympic opening ceremony rehearsal

Crowds at the technical rehearsal for the opening ceremony of the London Olympic Games have been told to 'save the surprise' for Friday's showpiece.

The hashtag #savethesurprise was displayed on the big screens inside the Olympic stadium, although many people have uploaded pictures to the internet.

Images on social media site Twitter depicted a raised grass platform in the middle of the stadium surrounded by man-made clouds that were held by string.

Those who had a ticket to the event, co-ordinated by Oscar-winning director Danny Boyle, may have experienced problems getting there as the Central Line of the underground was closed between White City and Liverpool Street.