The prime minister has refused to accept the resignation of a lord who offered to leave his post after being late to the chamber.

Lord Bates stunned colleagues in the House of Lords by stating his intention to resign after the "discourtesy" of arriving late to a session.

A spokesman for Number 10 said the resignation was "unnecessary" and he had decided to continue in his role.

Lord Bates could not immediately be contacted for comment.

The international development minister and former Conservative MP should have answered the first oral question of the session which began at 15:00 GMT on Wednesday.

'Hard-working and diligent'

A spokesman for the prime minister said: "With typical sincerity, Lord Bates today offered to tender his resignation, but his resignation was refused as it was judged this was unnecessary.

"As a hard-working and diligent minister, it is typical of his approach that he takes his responsibilities to Parliament so seriously.

"He has received support from across the House and we are pleased he has decided to continue in his important roles at the Department for International Development and HM Treasury."

Lord Bates, speaking to the Lords at the end of the questions session, described himself as "ashamed" to not have been in his place to answer a question from Labour's Baroness Lister.

"It's been my privilege to answer questions from this despatch box on behalf of the government," he told peers.

"I've always believed we should rise to the highest possible standards of courtesy and respect in responding on behalf of the government to the legitimate questions of the legislature.

"I'm thoroughly ashamed of not being in my place and therefore I shall be offering my resignation to the prime minister with immediate effect."

He then walked out of the chamber despite colleagues urging him to stay.