LONDON, July 13 (Reuters) - Foreign Secretary Liz Truss will set out her pitch to be Britain's next prime minister on Thursday in an increasingly bitter race to replace Boris Johnson, with a pledge to take the tough decisions and get economic growth going.
Truss came third in the first round of voting among Conservative lawmakers on Wednesday, behind former finance minister Rishi Sunak and junior trade minister Penny Mordaunt.
The remaining six candidates, which also includes former equalities minister Kemi Badenoch, Attorney General Suella Braverman, and Tom Tugendhat, chair of parliament's Foreign Affairs Committee, will face a second ballot on Thursday.
"I am ready to be prime minister on day one. I can lead, make tough decisions and rise to the moment," Truss will say as she launches her official campaign, according to excerpts released by her team in advance.
Truss will promise to support Britons facing a cost of living squeeze by reversing an increase in social security contributions that came into force in April, as well as lowering the tax burden on business and delivering economic reforms.
"I have a plan to make Britain a high-growth economy through bold supply-side reform," she will say.
The candidate with the lowest number of votes in the second ballot on Thursday will be eliminated, with further subsequent ballots being held among the Conservative lawmakers to whittle the field down to a final two by July 21.
The new leader will then be chosen from those two by the 200,000 Conservative party members in the country at large, and be announced on Sept. 5. (Reporting by Kylie MacLellan Editing by Alexandra Hudson)