The race to become Britain’s next prime minister was rocked on Saturday as the two contenders prepared to launch their rival head-to-head campaigns. News that police visited the home of runaway favorite Boris Johnson was splashed across newspaper front pages, raising questions about whether it would affect his prime ministerial hopes. Read more: Crowned, defined and destroyed by Brexit, UK PM Theresa May resigns The police visit was initially reported by the Guardian newspaper, which said officers were called to the home of Johnson and his partner, Carrie Symonds, in South London early on Friday. A neighbor told the paper they heard a woman screaming, followed by “slamming and banging” and shouting between Johnson and Symonds. The newspaper said it had obtained a recording of the incident. Boris Johnson making a campaign speech London’s Metropolitan Police confirmed that officers had been to the address after being alerted by a phone call. “The caller was concerned for the welfare of a female neighbor,” the police said in a statement. Police attended and spoke to all occupants of the address, who were all safe and well.” “There were no offences or concerns apparent to the officers and there was no cause for…