The Prime Minister will meet the German Chancellor Angela Merkel later today to push for his demands for reforms of the European Union.
Earlier this week, Mr Cameron said he was "sure" there would be treaty change in Europe.
"I'm absolutely convinced that there will be the need to reopen at some stage these treaties, not least to solve the problem of the eurozone".
Mr Cameron was also due to meet French President Francois Hollande on Monday but pulled out of the meeting, following the death of Baroness Thatcher.
More top news
The tin needed for a Mary Berry dish and the rules of mouse racing were among questions council call centres dealt with in the past year.
Scientists believe they have invented an ice cream that will melt slower in the sun.
There were shocks, tears and skimpy outfits at the star-studded MTV Video Music Awards in LA.