Loyalty pledge from Johnson at the London Mayor's Show Boris Johnson took the Conservative Party Conference by storm last night as he professed his loyalty to David Cameron but urged the Government to launch a huge housebuilding programme. The irrepressible Mayor of London told an ecstatic packed fringe meeting of about 1,500 Tory activists that the party was doing "a fantastic job" in government and was on course to win a majority at the 2015 election once the economy recovered. But he called for the Government to do more to build houses for middle income families, recalling that the Tories won elections when they did so. "We need to look after their interests," he said. He backed a return of grammar schools, which is not government policy, and spoke out against plans for a third runway at Heathrow Airport. We need a better solution," he said, calling for either expansion at Stansted or a new Thames Estuary airport. Mr Johnson tried to play down speculation that he was manoeuvring to be the next leader. "No one should have any cause to doubt my admiration of David Cameron," he said, pointing out that he urged Mr Cameron to run for the party's top job in 2005 as one of his early supporters. Last night the London Mayor was given a rock star's welcome and standing ovation before he had started speaking, at the ConservativeHome event billed as: "Boris 2012 Rally: Re-elected and Olympo-tastic." But, looking back at the Olympic Games which put him centre stage this summer, Mr Johnson insisted he was "the biggest harvester of undeserved credit." He announced that armed services would continue to enjoy free Tube travel if they were in uniform. Mr Johnson was mobbed by photographers and TV cameramen as he arrived at Birmingham New Street station. Boris!. During another media scrum at the Hyatt Hotel, he was asked if he was in Birmingham to make trouble for Mr Cameron. "I'm here to support the party," he replied. Although Cameron allies insisted they were relaxed about the London Mayor's Show, ministers were worried that he might again eclipse the Prime Minister, as he did during the Olympics. Mr Johnson will address the full conference today. But there was irritation that he had accused the Government of ignoring the "squeezed middle" championed by Ed Miliband.