On his first visit to the UK, Facebook founder and CEO Mark Zuckerberg has come to London to launch the "Facebook for Good: Share Your Story" programme.

"Three years ago, students in the UK first started to join Facebook", said Zuckerberg.

"Now, we have more than 12.6 million people in England, Scotland, Wales, and Ireland using the site to connect with their friends, share information, and contribute to making the world more open. I am happy to be here in London today to introduce a programme that celebrates the users and developers who’ve created a compelling Facebook experience in the UK."

The "Facebook for Good: Share Your Story" promo is all about the social networking company's "global commitment to empower individuals worldwide to positively influence people's lives".

Entrants are asked to submit a short essay and up to three photos that share their unique experiences about how Facebook has changed their lives, influenced the lives of their families and friends, or made a positive social impact.