Former Tory leadership candidate Mr Stewart said he has resigned from the Conservative Party and will stand down at the next general election.
The minister for international development is one of ten candidates to be Tory leader.
Stuart Davies, a member of Clwyd South Conservatives, shouted at the Prime Minister to resign as she began a speech to Welsh Tories in Llangollen. The National Convention don't want you, we don't want you,” shouted Mr Davies, who described himself as a loyal Conservative. Afterwards, he told journalists that Mrs May should resign “now”.
An exclusive poll of MPs found that 18% of Conservatives strongly support bringing back the death penalty and 13% somewhat support doing so.