Senior ministers are bracing themselves for Boris Johnson’s first major cabinet reshuffle since the Conservatives’ general election victory.

The PM will make a number of changes over the next 24 hours although it is unclear how wide-ranging they will be.

Attorney General Geoffrey Cox said he would be “uncomplaining” if, as some expect, he is sacked or moved.

Defence Secretary Ben Wallace told the BBC reshuffles were often “brutal”, but he was hopeful of staying in post.

Health Secretary Matt Hancock joked at an event in London: “It’s a huge pleasure to be here, and with a government reshuffle in the offing, it’s a great time to be talking about longevity.”

A Downing Street source told the BBC the PM would “reward those MPs who have worked hard to deliver on this government’s priorities to level up the whole country and deliver the change people voted for last year”.

Most of the cabinet have only been in their current jobs for just over six months, having been appointed when Boris Johnson became prime minister in July.

The PM left his cabinet largely untouched following his party’s decisive election victory in December, pending what sources suggested at the time would be a more significant overhaul after the UK left the EU on 31 January.

Senior figures such as Chancellor Sajid Javid, Foreign Secretary Dominic Raab and Home Secretary Priti Patel are not expected to be moved, but others are considered more vulnerable.

Mr Johnson is expected to make changes at junior ministerial level – namely parliamentary under-secretaries of state – that could see a 50/50 gender balance in a push to promote female talent.

There is also a plan to make at least 60% of parliamentary private secretaries women by the summer – compared with just 18% at the moment.