Three candidates for the Conservative Party leadership have signed a "clean campaign" pledge.
Health Secretary Matt Hancock, former Brexit secretary Dominic Raab and Home Secretary Sajid Javid signed up to a commitment not to "speak ill of fellow Conservatives".
The leadership contenders have urged the other confirmed candidates to sign up too, with Mr Raab saying the campaign should be a "battle of ideas not of personalities".
He added: "Whoever wins this election needs to bring the party back together so that we can take on and defeat Jeremy Corbyn. Fighting a clean campaign is essential if we want to unite our party again."
Mr Hancock said: "We shouldn't hold back when it comes to debating ideas, but this contest should be about policies not personalities.
"We'll all need to work with each other and come together as a party after this, so it's especially important that we don't engage in negative personal attacks and instead keep this contest focused on the issues."
Fellow leadership contender Rory Stewart later announced on Twitter he will be joining the Clean Campaign Pledge.
The five-point pledge includes commitments to stick to Conservative Party spending limits and to encourage supporters not to engage in abuse on social media.
It also says candidates will not allow third parties to spend money on online advertising, that they will not engage in personality attacks on others and they will not speak ill of fellow Tories.
There are so far 11 people who have announced their candidacy to succeed Theresa May, with MP James Cleverly the latest to join the race.
