Downing Street

Britain's Prime Minister David Cameron leaves Downing Street to see Queen Elizabeth II for the official dissolution of Parliament, in London, Monday, March 30, 2015. The United Kingdom will go to the polls for a general election on May 7. (AP Photo/Alastair Grant)

Alastair Grant/AP

Britain’s Prime Minister David Cameron leaves Downing Street to see Queen Elizabeth II for the official dissolution of Parliament, in London

LONDON, ENGLAND - MARCH 30: A fox runs in front of 10 Downing Street on March 30, 2015 in London, England. Campaigning in what is predicted to be Britain's closest national election in decades will start after Queen Elizabeth II dissolves Parliament today. (Photo by Carl Court/Getty Images)

Carl Court/Getty

A fox runs in front of 10 Downing Street in London, England. Campaigning in what is predicted to be Britain’s closest general election in decades will start after Queen Elizabeth II dissolves parliament today 

Britain's Chancellor of the Exchequer, George Osborne, holds up his budget case for the cameras as he stands outside number 11 Downing Street in central London...Britain's Chancellor of the Exchequer, George Osborne, holds up his budget case for the cameras as he stands with his Treasury team outside number 11 Downing Street, before delivering his budget to the House of Commons, in central London March 18, 2015.   REUTERS/Suzanne Plunkett (BRITAIN  - Tags: BUSINESS POLITICS TPX IMAGES OF THE DAY)

Suzanne Plunkett/Reuters

Britain’s Chancellor of the Exchequer, George Osborne, holds up his budget case for the cameras as he stands with his Treasury team outside number 11 Downing Street, before delivering his budget to the House of Commons, in central London

Royal Regiment Of Fusiliers March Through Whitehall To Protest Against Disbandment Of The Regiment...LONDON, ENGLAND - OCTOBER 15:  Former members of the Royal Regiment of Fusiliers prepare to march from Downing Street after handing in a petition to save the battalion on October 15, 2013 in London, England. The campaigners later gathered outside the Houses of Parliament in protest against plans to withdraw the battalion as part of the Ministry of Defence's plans to reduce the army by 20,000.

Dan Kitwood/Getty

Former members of the Royal Regiment of Fusiliers prepare to march from Downing Street after handing in a petition to save the battalion in London, England. The campaigners later gathered outside the Houses of Parliament in protest against plans to withdraw the battalion as part of the Ministry of Defence plans to reduce the army by 20,000.

A police officer stands guard as Larry, the cat, waits to be let in to Number 10 Downing Street in London...A police officer stands guard as Larry, the cat, waits to be let in to Number 10 Downing Street in London August 30, 2013. Prime Minister David Cameron's plans to join a potential military strike on Syria were thwarted on Thursday night when Britain's parliament narrowly voted against a government motion to authorise such action in principle.     REUTERS/Toby Melville

Toby Melville/Reuters

A police officer stands guard as Larry, the cat, waits to be let in to Number 10 Downing Street in London. Prime Minister David Cameron‘s plans to join a potential military strike on Syria were thwarted on Thursday night when Britain’s parliament narrowly voted against a government motion to authorise such action 

Britain's Prime Minister Cameron leaves 10 Downing Street in London...Britain's Prime Minister David Cameron leaves Number 10 Downing Street to attend parliament in London August 29, 2013. Britain's parliament has been recalled to vote on how to respond to Syria's suspected use of chemical weapons. REUTERS/Suzanne Plunkett (BRITAIN - Tags: POLITICS CONFLICT)

Suzanne Plunkett/Reuters

David Cameron, UK prime minister, leaves Number 10 Downing Street to attend parliament in London on Thursday. Britain’s parliament has been recalled to vote on how to respond to Syria’s suspected use of chemical weapons