From Google.co.uk:

“At Google, we like to reflect the ever changing world of our users through the logo designs on our homepage. These “doodles” celebrate different people, events or special dates and, until now, have been designed by our original Doodler, 28-year-old Dennis Hwang.

The ‘Doodle 4 Google – My Britain’ competition asks young people across the UK to design a doodle that represents what it means to be British today. The winning doodle, which will be displayed on the Google UK homepage for a day, will be seen by around 18 million people.

This is the first nationwide Doodle 4 Google competition and is open to every school in the UK.”

NOTE:
Entries to the competition have now closed. The finalist doodles will be displayed on the google.co.uk site in October for a public vote which will select the winners. Please return then to vote for your favourite.