Reid and Blair top the list of MPs who just can't answer a straight question

Tony Blair is one of Westminster's worst wafflers, according to research.

The Prime Minister gives a direct answer to only 40 per cent of questions - and avoids replying 42 per cent of the time.

And despite his reputation as a straight-talking Home Secretary, John Reid is even more slippery than his boss. He gives no response to 44 per cent of questions posed while giving a full answer to only 36 per cent.

A team led by the Professor Geoff Beattie, dean of psychology at Manchester University, analysed every political TV interview by the ten highest-profile MPs over three weeks.

Replies were categorised as "direct", which was a full answer, "intermediate" - a partial answer - or "no response", where the politician either refused to answer or gave an irrelevant reply.

And the study found there might be some truth in the old saying: "If you want a straight answer to a straight question, don't ask a politician."

Overall, they offered direct replies to 46 per cent of questions, partial answers to 23 per cent and totally irrelevant answers to 31 per cent.

The report said: "The majority of the time MPs are either off on their own agenda, ducking the question completely, giving a partial answer or merely hinting at an answer, without actually stating it."

It found that Mr Reid was the worst culprit for dodging issues and using unnecessarily longwinded language when answering a interviewer's question. On one occasion, he was asked by BBC1's Andrew Marr: "Do you expect Gordon Brown to take over from Tony Blair, yes or no?"

Instead of giving a straight answer, he replied: "I've already told you that I'll tell you that when the time comes and I have said in the past that it's discourteous to the present Prime Minister."

Mr Blair comes a close second with the number of non-replies, 42 per cent. The report says: "He often employs a clever technique of responding to a question within its broad parameters, before moving on to his own agenda, which does not answer the question posed."

Gordon Brown avoided answering directly 32 per cent of the time. But he scored the most direct answers of any senior Labour politician with 47 per cent.

The report, published yesterday, said: "Tactics such as simply not replying to questions that he feels are unacceptable, and in particular deflecting questions that would require personal or emotional responses, are all part of the Brown charm offensive."

Deputy Prime Minister John Prescott made the top three with 39 per cent of non-replies. Tory home affairs spokesman David Davis was the least evasive politician, giving direct replies to 57 per cent of questions.

Lib Dem leader Sir Menzies Campbell and his home affairs spokesman Nick Clegg were also straight-talking, giving direct answers to 54 per cent and 52 per cent of questions respectively.

Tory leader David Cameron was a master of the partial reply, giving one 36 per cent of the time.

The study said: "Politicians who do this are still hedging their bets on a number of issues, by very adeptly answering only part of the question or implying an answer."

Mr Cameron and Shadow Foreign Secretary William Hague gave direct answers to 47 per cent of queries.

Ash Makker, marketing director of Teletext, which commissioned the research, said: "This reveals the tactics Britain's top politicians use day in, day out, to get their message across and avoid difficult questions."