Liz Truss will make an urgent attempt to overtake her main rival, Penny Mordaunt, in the Conservative leadership race with a pledge to raise defence spending and a vow to look again at the size of the UK armed forces.
The foreign secretary is facing an uphill battle to join Rishi Sunak in the final two of the contest, as well as an insurgent campaign by the fourth-placed Kemi Badenoch, who picked up more supporters than Truss at the last round of voting.
