Prime Minister David Cameron said the whole country would join him and wife Samantha in wishing Prince William and Kate Middleton "great joy" upon the news of their engagement.

In a statement, Mr Cameron said: "I am delighted to hear this wonderful news. I am sure the whole country will join Samantha and me in wishing them great joy in their life together."

Labour leader Ed Miliband said: "I'm delighted for Prince William and Kate Middleton and send them my very best for their wedding. The whole country will be wishing them every happiness."

Asked about the engagement after addressing a gathering of business leaders at KPMG in Canary Wharf today, Mayor of London Boris Johnson said: "I think it's fantastic.

"I'm very pleased for the pair of them and wish them every possible success and happiness.

"Everybody is pleased. In a weird way, it (a royal wedding) cheers everyone up."