Britain would lose influence if it were to leave the European Union, the Vice-President of the European Commission has said.
Speaking in Cambridge, Viviane Reding said that a UK outside the EU "would have to live with the rules decided on by the other EU countries".
Ms Reding said talks of renegotiations and referenda "distracts from the real issue".
"Finding more solutions like the ones [found for the banking and financial sector] is what we should all be focusing our energy and creativity on."
More top news
The US president, who has not visited the UK since being elected, is reported to be planning a summer trip to Britain.
Mack entered her plea in federal court in Brooklyn. The judge refused a request by her lawyers to release her without bail.
Officers investigating a reported break-in on Friday found 22-year-old Roger Alvarado asleep in the pop star's home in Tribeca.