LONDON, June 30 (Reuters) - British lawmaker Andrea Leadsom, a prominent campaigner for Britain to leave the European Union, said on Thursday she would be standing as a candidate to replace Prime Minister David Cameron as Conservative leader.

Cameron, who led the Remain campaign, announced last week he would quit after Britons voted to exit the EU with his replacement due to be announced in early September.

"Delighted to say I'm running for the @Conservatives Leadership," Leadsom, a junior energy minister who previously had a long career in finance, wrote on Twitter.

(Reporting by Michael Holden; editing by Guy Faulconbridge)