The Forest of Dean's Mark Harper is the latest Tory MP to throw his hat into the ring to become the next prime minister.
A dozen Conservatives have now declared their intention to fight for the top job once Mrs May resigns as leader on June 7.
The former Chief Whip has not served in Mrs May's government and admits he is an ‘underdog’ in the leadership contest.
Who is Mark Harper?
Mark Harper has been the MP for the Forest of Dean since 2005.
Whilst he has been on the back benches for the time Theresa May has been in charge, he held a number of senior roles under her predecessor.
He was Immigration Minister at the Home Office, Disabilities Minister at the DWP, and was also a minister in the Cabinet Office.
After the 2015 election he was promoted to the Cabinet and was former Prime Minister David Cameron’s Chief Whip for a year.
What are his chances?
Harper isn’t the best known of the candidates but has a reasonable amount of Government experience behind him.
As Chief Whip for a brief time, he will have had a lot of contact with MPs who will now decide how long he can stay in the race.
He already has support from more MPs than some of the other candidates, but front-runners Boris Johnson and Michael Gove are still out ahead.
Although that could all change next week when Parliament returns from recess.
Where does his stand on Brexit?
On Brexit he voted to remain but since the referendum he has always said his party must deliver it.
He is a party loyalist, although Theresa May’s deal tested that loyalty too far.
He only backed her Withdrawal Agreement on the third time of asking, for fear that it was the only way to deliver Brexit.
What makes him stand out?
His pitch is to unite the party and says he has an edge over his rivals as they ‘shared the responsibility’ for Theresa May’s failure to deliver Brexit.
Harper is popular with many MPs and chairs the informal group of South West Tory MPs who meet on a regular basis.
He is a regular performer in the media and hasn’t been tied up in the cabinet arguments over Brexit.
He will be seen by some to have the experience needed for the top job but without the baggage of some of his rivals.
Watch the full interview with Mark Harper: