A series of events have been planned to highlight the landmark as the countdown to the Games begins in earnest.

Deighton said: "We are absolutely where we want to be with 100 days to go - we are ready to welcome the world to London.

"Millions of people around the UK are getting ready to celebrate the biggest event in sport.

"Eight million of the 11million tickets have been sold to people in Britain and we are sure that Brits will get hold of a chunk of the other three million too."

Many of the test events have already been held at the venues, but the biggest yet will be on the first weekend of May with a cluster of events in the Olympic Park where 80,000 people are expected to attend, including 50,000 spectators in the Olympic Stadium to watch the London Disability Athletics Challenge.

Deighton said many lessons had already been learned from the test events, including in relation to security procedures.

There have also been opportunities to improve some of the venues for sports.

The BMX track has been altered to cut the effect of high wind at the first jump, and the surface has also been changed after rain at the test event last August caused problems for the cyclists.

Modern pentathlon have brought in changes to their shooting event, while the basketball arena has been altered so that players do not have to go outside when walking from their waiting area into the arena.

Technology

Deighton said: "The test events have done what we really wanted them to do which was to give a real test on the field of play, to make sure that the surfaces and technology is right.

"It also gives an opportunity to bring the workforce for that venue together in an operational sense, and experience how the team operates at that venue.

"It has been quite reassuring. Things have gone wrong, because things always do go wrong at events, and the issue is to have the teams in place to fix these things. Nothing however has made us radically change our plans."

Organisers have also been able to monitor the speed of queues while spectators are going through security checks.

This was tested rigorously at the beach volleyball event at Horse Guards Parade, a stone's throw from the House of Commons, where it emerged that even the weather could have an effect on the movement of the queues.

"We have been forensic with what we have tested, where," added Deighton. "At Horse Guards Parade with beach volleyball we did a very careful test of the security screening and understanding what makes lines go faster and slower.

"It is very helpful to know the effect of rain on the speed of the lines for example."