It has become a coveted emblem of endeavour, worn with pride by thousands of school children across Britain and awarded to the likes of David Beckham, Sir Elton John, the Queen...and even the Forth Bridge.

And tomorrow the Blue Peter badge celebrates 50 years in circulation.

In that time, the programme's famous pin has been handed out to a host of sporting and screen stars as well as an ever-expanding list of animals - including Endal, a labrador that was said to have saved its owner's life.

The badges were launched on June 17, 1963, and since then have been dished out to around 22,000 recipients each year.

The Queen was presented with her Blue Peter badge when she visited the programme's studios in 2001.

Now the pins come in six colours. Blue badges can be won by viewers who send an interesting letter, poem, picture or story to the programme, with anyone making a second contribution receiving a silver pin.

Green recognises environmental contributions, orange badges are handed to Blue Peter competition winners or runners-up and purple pins go to children who take an active role in a show.

A gold badge - the highest honour - is given out following an outstanding achievement or handed to those who have demonstrated exceptional bravery.

A total of 764 gold badges have been awarded to children, while one was given to a pony named Jet and six have been handed to dogs.

Last year, the Forth Bridge, one of Scotland's most famous landmarks, was also awarded a gold Blue Peter badge, becoming the first structure to earn the prize in recognition of the "thousands of workers that risked their lives to build it".

Other recipients of the gold badge include Gary Barlow, Tiger Woods, Ewan McGregor, Damien Hirst and racing driver Lewis Hamilton who appeared on the show twice when he was young - first when he was interviewed by John Leslie while operating a remote control car and later, during a go-karting feature on the programme.

The gold pins have also been handed out to the illustrator Sir Quentin Blake, film director Tim Burton and Olympic gymnast Beth Tweddle.

Earlier this month, Blue Peter launched a new "sports badge", which will be available for a limited time and awarded to children who can demonstrate a contribution to the development of a sporting legacy following last summer's Olympics.