Theresa May looks set to be confirmed as leader of the Conservative Party and the UK's second female prime minister, after her only remaining rival sensationally dropped out of the race to succeed David Cameron.

Andrea Leadsom announced she was quitting the contest shortly after apologising to the Home Secretary over an interview in which she appeared to suggest that the fact she was a mother gave her the edge over the childless Mrs May as a future PM.

Speaking on the steps of her campaign HQ in Westminster, the Energy Minister wished Mrs May "the very greatest success" and promised her "my full support".

The chairman of the Conservative backbench 1922 Committee, Graham Brady, said he needed to consult with the party's board before formally confirming that Mrs May was the new leader.

He said he was hoping to hold discussions this afternoon, but was unable to say whether Mrs May would be confirmed as Prime Minister by the end of the day or the week.

Meanwhile, Justice Secretary Michael Gove, who came third in the leadership ballot among Tory MPs, pledged his backing to Mrs May, saying: "Andrea Leadsom spoke with great dignity and courage today. I wish her every success in the future.

"We should now move as quickly as possible to ensure Theresa May can take over as leader. She has my full support as our next Prime Minister."

Former London mayor Boris Johnson - who abandoned an expected tilt for the leader's job after realising he faced competition from both Mrs Leadsom and Mr Gove - said he had "no doubt" that Mrs May would make an excellent party leader and PM.

Mr Johnson said: "Theresa May will provide the authority and the leadership necessary to unite the Conservative Party and take the country forward in the coming weeks and months.

"Andrea's decision, which is both brave and principled, allows that process to begin immediately.

"I have no doubt Theresa will make an excellent party leader and Prime Minister and I'm encouraged that she's made it clear that Brexit means Brexit - that we will leave the EU.

"It is vital that we respect the will of the people and get on with exploiting new opportunities for this country."