The jagged emblem, based on the date 2012, comes in a series of shades of pink, blue, green and orange and will evolve in the run-up to the Games.

The word London and the Olympic rings are included in the first two digits of the new logo.

"This is the vision at the very heart of our brand," said London 2012 organising committee chairman Seb Coe.

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Interactive Olympics editor Claire Stocks

"It will define the venues we build and the Games we hold and act as a reminder of our promise to use the Olympic spirit to inspire everyone and reach out to young people around the world.

"It is an invitation to take part and be involved.

"We will host a Games where everyone is invited to join in because they are inspired by the Games to either take part in the many sports, cultural, educational and community events leading up to 2012 or they will be inspired to achieve personal goals."

The new design, which cost £400,000, has received a mixed response, but Lord Coe was adamant it put across the image and message that he wanted the London Games to deliver to the world.

"It's not a logo, it's a brand that will take us forward for the next five years," he told BBC Five Live.

When people see the new brand, we want them to be inspired to make a positive change in their life

Tony Blair

"It won't be to be eveybody's taste immediately but it's a brand that we genuinely believe can be a hard working brand which builds on pretty much everything we said in Singapore about reaching out and engaging young people, which is where our challenge is over the next five years.

"If we don't do that, then frankly the whole project is unsustainable."

For the first time the same logo will be used for both the Olympic and Paralympic Games.

Organisers hope the brand will boost the marketing push to raise £2bn to stage the Games and convey the message that London 2012 will be "Everyone's Games".

Prime Minister Tony Blair said: "We want London 2012 not just to be about elite sporting success.

"When people see the new brand, we want them to be inspired to make a positive change in their life.

"London 2012 will be a great sporting summer but will also allow Britain to showcase itself to the world."

Lord Coe wants the branding to appeal to young people

International Olympic Committee President Jacques Rogge said: "This is a truly innovative brand logo that graphically captures the essence of the London 2012 Olympic Games - namely to inspire young people around the world through sport and the Olympic values.

"Each edition of the Olympic Games brings its own flavour and touch to what is now well over a century of modern Olympic history; the brand launched today by London 2012 is, I believe, an early indication of the dynamism, modernity and inclusiveness with which London 2012 will leave its Olympic mark."

The brand, designed by Wolff Ollins, has been targeted at the young people the organisers hope will get involved.

It is a deliberate change from previous Olympic logos, which often feature an image from the city.

Olympics Minister Tessa Jowell said: "This is an iconic brand that sums up what London 2012 is all about - an inclusive, welcoming and diverse Games that involves the whole country.

"It takes our values to the world beyond our shores, acting both as an invitation and an inspiration.

"This is not just a marketing logo, but a symbol that will become familiar, instantly recognisable and associated with our Games in so many ways during the next five years."

606: DEBATE

British Paralympic Association chief executive Phil Lane believes that having one logo for both the Olympics and Paralympics is a positive move.

"As the founding nation for the Paralympic movement it is fitting that Britain should lead the way in integrating the two Games," he said.

"We hope that the brand will succeed in inspiring Britain's youth and Paralympic athletes to success."

Plans have also been drawn up to create a different logo for grassroots projects backing the Games.

It would not include the Olympic rings but would spread the benefits of hosting the Games to projects involved in its grassroots cultural, environmental and sporting work.

A London 2012 spokeswoman said: "It is not going to be a free for all. There would be conditions to qualify for it.

"It is not about giving it out to people so that they do not pay for it. It is about an emblem that could be a stamp of endorsement that really fits in with the legacy of the Games."

London Mayor Ken Livingstone added: "The new Olympic brand draws on what London has become - the world's most forward-looking and international city.

"That message of welcome and diversity was one of the main reasons for London's success in winning the Games.

"We offer the world the same exciting message that in 2012 every athlete and every visitor will feel at home in our city."