Acertain ambiguity': the hounds of Fleet Street yet again dug their teeth into Mr Roy Hattersley after he had answered questions on television about the Labour Party's new defence document, picking on his weakest phrase for their headline. Mr Hattersley yet again failed to sink. So often has he been punctured by questions about Labour's defence policy that he must now be reckoned unsinkable. His strange, waterlogged buoyancy ceases to be contemptible. He has become a wonder of our politics, the stunt man who never tires of trying to leap unleapable gaps, and whose falls, though they slow him and his party down, are never im- mediately fatal. Mr Hattersley was to have accompanied the courageous Mr Kaufman on the mission, before the general election, to urge Mr Foot to resign as party leader. He funked it. But did he stay quiet as a mouse about this inglorious episode? No, he found the craving to have it both ways too strong, and let it be known that he had wanted to accompany Mr Kaufman. Con- cerning defence, however, Mr Hattersley seemed at length to have made a firm decision. The National Executive Commit- tee had been given a choice of two word- ings for the section on unilateral disarma- ment. One read: `. . Labour will on assuming office decommission Polaris from service.' The other read: 'Any decision on the timetable for decommissioning Polaris must inevitably depend on the outcome of the arms reduction negotiations. We are fully committed to the success of such negotiations.' Mr Hattersley, whose own opinions were thought to be in accord with the second alternative, proposed to the NEC that the first should be adopted. That looked to be Hattersley settled once and for all. Four days later he was on television talking about a new flaw, discovered in the plan to adopt a non-nuclear role but remain a proper member of Nato. The Americans would be quite happy to keep their conventional bases in Britain even if they had to dismantle the nuclear ones. They would never go home. All was well. But, on the other hand, there was a certain ambiguity. Truly this unilateralist's educa- tion is a painful one.