UK PM race: Ben Wallace drops out, Rishi Sunak early frontrunner

"After careful consideration and discussing with colleagues and family, I have taken the decision not to enter the contest for leadership of the Conservative Party," Wallace said on Twitter.

British Defence Secretary Ben Wallace, one of the favourites to succeed Prime Minister Boris Johnson, on Saturday ruled himself out of the leadership race. "After careful consideration and discussing with colleagues and family, I have taken the decision not to enter the contest for leadership of the Conservative Party," Wallace tweeted on Saturday amid the ongoing political crisis.

British Defence Secretary Ben Wallace arrives at 10 Downing Street, in London. (REUTERS)

"It has not been an easy choice to make, but my focus is on my current job and keeping this great country safe."

Wallace, 52, has risen in recent months to overtake Foreign Secretary Liz Truss as the most popular member of the government with Conservative Party members, according to Conservative Home, thanks to his handling of the Ukraine crisis.

Wallace's resgination's has strengthened the Rishi Sunak's position in the party as the new conservative leader.

The 42-year-old son-in-law of Infosys co-founder Narayana Murthy has received the public backing of several senior Tory members of Parliament, including Commons leader Mark Spencer, former party chairman Oliver Dowden and former Cabinet minister Liam Fox.