UPDATED REPORT Richard Prebble has resigned as leader of the ACT Party, he announced today. He told a press conference that it was the best thing for the party, which has been struggling in the polls. His resignation comes just an hour after Act MPs collectively said there was no threat to his leadership. Just yesterday Prebble dismissed speculation he was about to resign, saying the leadership issue was not being discussed at today's caucus meeting. "No one has raised it with me in the last four weeks," he said. Despite his confidence there had been rumours of his demise...