Former Home Secretary Priti Patel, who declared backing for Boris Johnson as UK PM, said on Monday that she is setting aside political differences to give fellow India-origin Rishi Sunak "the best chance of succeeding".

Patel, who has served in former Prime Minister Boris Johnson's Cabinet, switched support after former PM Johnson pulled out of the race on Sunday night.

"In these difficult times for our country we must unite by putting public service first and work together. We care about our country and with the enormous challenges upon us we must put political differences aside to give @RishiSunak the best chance of succeeding," Patel wrote on her Twitter handle.

Sunak looks set to become UK's next prime minister after he got support of more than 170 members of the parliament -- much beyond the 100-mark required to bag the keys to 10 Downing Street.

Penny Mordaunt, the only other candidate, is making a last ditch attempt to persuade Tory MPs for support. She has just 26 declarations.

Sunak made the renewed attempt to contest for the post, just weeks after losing to Liz Truss in the summer leadership contest.

"I want to fix our economy, unite our party and deliver for our country," the former chancellor said in a short statement confirming his widely expected candidacy.

Along with Patel, senior Conservative leader and former environment secretary Michael Gove also backed Sunak for PM in the 'interest of the nation'.

"It is time now for the Conservative party to unite behind @RishiSunak - there are big challenges ahead and the national interest requires us to show resolution and fortitude under new leadership.

By Sunday it was clear that Sunak had strong support from different factions in the Conservative Party with centrist MPs and even the extreme right-wing Suella Braverman coming out in his favour. Braverman had resigned last week from Prime Minister Liz Truss's government.

Sunak is the son-in-law of Infosys founder N R Narayana Murthy.