By Andrew MacAskill and Michael Holden NEWCASTLE-UNDER-LYME, England (Reuters) – John Jones is the sort of voter that British Prime Minister Boris Johnson cannot afford to lose – but already has. Jones, who backed Johnson’s Conservatives at the national election three years ago when the party swept to a landslide victory, regrets his decision after the prime minister broke his own coronavirus lockdown laws to attend alcohol-fuelled gatherings in his Downing Street office. The 75-year-old retired hospital supplies manager said he won’t vote Conservative again until Johnson has gone. “I am absol…