ALTHOUGH the focus of reporting of yesterday's Populus opinion poll for The Times has been the continued decline in the public's assessment of Tony Blair's trustworthiness, the party leader who needs to be most worried about the poll's findings is actually Iain Duncan Smith. At a time when the government in general and Mr Blair in particular have been going through a harrowing period of failure and confusion the main beneficiary in the public's attitude is not the leader of the Opposition but Charles Kennedy of the Liberal Democrats. Mr Kennedy's party has advanced four percentage points in terms of voting intentions and he himself is considered he most popular and trusted of the three leaders. According to the Populus poll, voting intentions if there were a general election this week would be: Labour 34 per cent (down two points since early July); Conservatives 32 per cent (down two points also); Liberal Democrats 25 per cent (up four points). The Liberal Democrat performance follows a familiar pattern for mid-term polling; when the real election comes along few people suppose that the party could form a government and vote accordingly for Conservatives or Labour (or abstain). The continuing failure of the Conservatives under Mr Smith to take advantage of Labour's troubles, as the Liberal Democrats have done, demonstrates how little appeal the party has as an alternative government. With at least two years to go before a general election it is still not too late for the Conservatives to decide to replace Mr Smith with a more dynamic leader; if they do not the party is probably facing another six or seven years in opposition.