Senior UK ministers have called for a truce in a heated debate on Britain's membership of the European Union, saying the ruling Conservative Party must be civil if it wants to stay in power.
The party is deeply split over whether Britain should vote to stay in the EU at a referendum on June 23, and several allies of Prime Minister David Cameron, who supports EU membership, are campaigning to leave the 28-member bloc.
Some politicians have criticised Cameron for accusing London Mayor Boris Johnson, a leading Conservative, of putting his own ambition above his beliefs by backing the "Out" campaign.
They said the thinly veiled attack last week on Johnson, the most prominent party member in the "Out" camp, violated an unwritten rule that both sides respect each others' opinions.
"Everyone has to go out of their way to make sure that the debate within the Conservative Party is a constructive one, an amicable one and one that doesn't involve attacks on each other," said Christopher Grayling, leader of the House of Commons who supports leaving the EU.
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"And then, from a Conservative point of view, after the event we've really got to make sure that when the result comes in, we come together, we heal the party, we move beyond the discussions at the moment and we win in 2020," he told Sky News on Sunday.
Cameron has allowed party members to campaign according to their conscience, saying he can't force them to back his campaign in support of EU membership.
Many of Britain's leading businesses have said they want to remain in the European Union and the opposition Labour Party has said it will campaign to stay in, overcoming the euroscepticism of its leader, veteran anti-war campaigner Jeremy Corbyn.
