Several of the editorial cartoons in today's UK national dailies use the controversial incident in which a Chelsea footballer kicked a ball from under a time-wasting ballboy—and was sent off for violent conduct (see here for full story)—as a metaphor for Britain's relationship with the EU, following David Cameron's keynote Europe speech on Wednesday.
In this cartoon by Paul Thomas from The Daily Express, David Cameron is portrayed as the footballer getting the ball back from the EU ballboy. The ball can be seen as a metaphor for the powers which Cameron is seeking to repatriate from Brussels to Britain.
In this one by Bob from The Daily Telegraph, the roles are reversed. Cameron is shown as the ballboy holding on to the British ball, which several EU footballers are trying to take away from him. In this case, the ball could be seen as a symbol of British sovereignty, which Cameron is trying to protect from EU interference.
Peter Brookes from The Times has a slightly different take on the incident. He shows Cameron kicking the UK ball from under Nigel Farage, leader of the UK Independence Party. (One of the reasons being suggested for Cameron's promise to hold a referendum on Europe is that he wants to halt the progress of UKIP, which has long demanded such a referendum). By coincidence, Chelsea's kit is blue, just like the Tory Party's official colour.
To extend the footballing metaphor, you could say that the question of Britain's EU membership is a political football. A political football is a political topic or issue that is continually debated but left unresolved. The term is used often during a political election campaign to highlight issues that have not been completely addressed, such as the natural environment and abortion (source: Wikipedia).