Gordon Brown has tonight resigned as Prime Minister.

Mr Brown announced his intention to leave office in a speech outside Number 10 at 7.20pm.

With his wife Sarah at his side, Mr Brown said he was standing down both as Prime Minister and leader of the Labour Party with immediate effect.

Mr Brown’s decision came five days after the General Election left Britain with a hung Parliament and ushered in a coalition of the Conservative and Liberal Democrat parties.

In his speech Mr Brown said his period in office had been a privilege, and he had learned much about the best in human nature and also its frailties – including his own.

“I loved the job for its potential to make this country I love fairer, more tolerant, more green, more democratic, more prosperous and more just – truly a greater Britain.

“In the face of many years, challenges up to and including the global financial meltdown, I have always tried to serve, to do my best in the interests of Britain, its values and its people.”

Mr Brown paid tribute to Britain’s armed forces and said he would never forget those who had died for their country, or their families.

He then set off for Buckingham Palace to submit his resignation to the Queen.

The Palace said Mr Brown’s resignation was accepted at 7.45pm.

The full text of Mr Brown’s speech:

“As you know after the General Election, that left no party able to command a majority in the House of Commons, I said I would do all that I could to ensure a strong, stable and principled government was formed; able to tackle Britain’s economic and political challenges effectively.

“My constitutional duty is to make sure that a government can be formed following last Thursday’s General Election.

“I have informed the Queen’s private secretary that it is my intention to tender my resignation to the Queen.

“I have been privileged to learn much about the very best in human nature, and a fair amount, too, about its frailties, including my own.

“In the event the Queen accepts, I shall advise her to invite the leader of the opposition to seek to form a government.

“I wish the next prime minister well, as he makes the important choices for the future.

“Only those who have held the office of prime minister can understand the full weight of its responsibilities and its great capacity for good.

“I have been privileged to learn much about the very best in human nature, and a fair amount, too, about its frailties, including my own.

“Above all, it was a privilege to serve and, yes, I love the job, not for its prestige, its titles and ceremony, which I do not love at all, no, I loved the job for its potential to make this country I love fairer, more tolerant, more green, more democratic, more prosperous and more just – truly a greater Britain.

“In the face of many years, challenges up to and including the global financial meltdown, I have always tried to serve, to do my best in the interests of Britain, its values and its people.

“And let me add one thing also, I will always admire the courage I have seen in our armed forces.

“Now the political season is over, let me stress that having shaken their hands and looked into their eyes, our troops represent all that is best in our country, and I will never forget all those who have died in honour and whose families today live in grief.

“My resignation as leader of the Labour Party will take effect immediately, and in this hour I want to thank all my colleagues, ministers, members of Parliament, and I want to thank above all my staff who have been friends as well as brilliant servants of the country.

“Above all I want to thank Sarah for her unwavering support as well as her love and for her own service to our country.

“I thank my sons John and Frazier for the love and joy they bring to our lives and as I leave the second most-important job I could ever hold, I cherish, even more, the first as a husband and father.

“Thank you and goodbye.”