A prominent journalist has declared Theresa May is not fit to be Prime Minister because she "lacks any capability."
May recently appointed Gavin Williamson, the former Chief Whip, to the Cabinet as Defence Secretary.
His predecessor, Sir Michael Fallon, resigned on Wednesday after allegations about improper behaviour in the past.
Mellor, who was a former Cabinet minister under John Major, said his appointment represented Theresa May's "cronyism."
He told Paul Ross: "The first thing to say is the complete breakdown of party discipline within the Tories.
"What we wanted from Theresa May was a steady the ship leadership.
"What she has done with the appointment of Gavin Williamson, is done something provocative, she seems to be even more commited to cronyism than David Cameron was.
“That seems to me to show she lacks any real capability to be Prime Minister.
"I’ve never felt so utterly depressed as I do now about the state of British politics."