Tory leadership hopeful Rory Stewart insisted his ambition to replace Theresa May would not interfere with his job running the UK’s international aid department.
International Development Secretary Mr Stewart said he was one of at least six Cabinet ministers with their sights on Number 10.
But he faced questions about whether he could balance the demands of his first Cabinet job with a leadership campaign.
He was questioned by Tory MP Nigel Evans as he appeared before the Commons International Development Committee.
Mr Evans asked “how can we be absolutely convinced that you are committed totally to the job you have just been put into” when “you could be in a leadership election in the next few weeks”.
Mr Stewart, who was appointed in a reshuffle on May 1 following Gavin Williamson’s sacking as defence secretary, said he had the advantage of considerable experience at the Department for International Development.
“I completely understand where you are coming from,” he told Mr Evans.
“I have some advantages taking over this job. I am probably the only Secretary of State who occupied every Commons junior ministerial role in this department before I took over.
“I understand therefore our programmes in the Middle East, Asia and Africa in enormous detail.”
The former diplomat added that he had spent “much more of my working life in international development than, I assume, anyone else who has taken over this job”.
He added: “It is true that the Prime Minister has signalled that she is stepping down and therefore I, and at least half-a-dozen other Cabinet colleagues, have expressed interest in succeeding her.
“But I am sure they, like me, will remain entirely committed to doing our jobs as powerfully as possible.”