An opinion poll suggests that three out of four Britons think Prime Minister Gordon Brown has been a change for the worse compared to his predecessor, Tony Blair. The ICM poll published in Wednesday's Guardian newspaper says support for Brown's Labour Party had fallen to 25 percent. That was 20 points behind the opposition Conservatives, and the biggest gap ever recorded by ICM. Brown had a brief spell of popularity when he took over from Blair a year ago, but a series of polls have said his party is lagging behind the Conservatives. ICM interviewed a random sample of 1,000 adults aged 18 and over by telephone between June 20 and 22. The survey had a margin of error of plus or minus 3 percentage points.