Home Secretary Teresa May returned from holiday Monday to meet police chiefs following the outbreak of sporadic rioting around London over the weekend. Home Secretary cuts short holiday trip to examine London riots There was no immediate indication of whether Prime Minister David Cameron would come back from his holiday in Italy, but pressure was mounting on London Mayor Boris Johnson, who has been lampooned on the internet for not appearing to take the crisis seriously, to also return from his holidays. The police also faced criticism over its reaction following last month\'s resignation of Metropolitan Police Chief Commissioner Sir Paul Stephenson and Assistant Commissioner John Yates over the phone hacking scandal engulfing Rupert Murdoch\'s News International. Acting Commissioner Tim Godwin, who is due to meet May, appeared at a press briefing Monday after being criticised for adopting a low profile, saying there must be a separation between \'grievance and criminality\' in handling the rioting. Deputy Prime Minister, who said he has spoken to Cameron, described the violence as “completely unacceptable” but concern was that the rioting could continuing for a third night and even spread outside London. Further doubts were also cast about the official version of Thursday\'s police killing of Mark Duggan, which triggered the rioting, about it being the result of an exchange of fire, with reports suggesting that a bullet injuring a police officer was fired by another police marksman and not Duggan.