Tony Blair didn't make the top five and Margaret Thatcher trails to a Welsh windbag. As the result of a poll to find the most successful 20th century occupant of 10 Downing Street is announced, Nick Morrison looks at what makes a good prime minister

HE was an unassuming man whose holidays were spent motoring around Ireland with his family. To look at, he resembled perhaps a middle-ranking civil servant, or perhaps the Army officer he had once been. Winston Churchill struck a chord with many when he described him as: "A modest man who has a good deal to be modest about."

Yet Clement Attlee was last night named as the most successful prime minister of the 20th century, triumphing over Churchill, both his one-time adversary and his colleague.

He may have lacked the powers of oratory of David Lloyd George (3rd), the energy of a first-term Harold Wilson (10th) or the zeal of Margaret Thatcher (4th), but it was Attlee's achievement to lead perhaps the most influential government of the last century.

In the creation of the welfare state, the NHS, comprehensive education and social security, much of his government's legacy still stands, and the post-war consensus which it established lasted for 30 years. Many of the nationalisations may have been reversed, but few governments have had as far-reaching and long-lasting impact.

Second to Attlee was Churchill, whose position owes more to his wartime leadership than his post-war premiership, followed by Lloyd George and Thatcher.

The poll, commissioned by Leeds University, asked 139 academics to rank the 20 prime ministers of the 20th century, and, although a left-wing bias was to be expected, the result is no surprise, according to Nick Randall, politics lecturer at Newcastle University.

"The achievement of Attlee was that the country was in dire straits after the war and not only did the government succeed in restoring the economy and setting the country up for the post-war boom, but his administration genuinely did change the country for the better," says Dr Randall, one of those who took part in the poll (he put Churchill above Attlee).

'The welfare state reforms and the contribution on the international front - pretty instrumental in setting up NATO - means it is commonly regarded as the most successful Labour administration and the high-water mark of social democracy in Britain."

But while it may be his government's achievements which give Attlee pole position among premiers, it is his style which marks him out from many other holders of the office. The polar opposite of Tony Blair's (6th) presidential approach, Attlee left his ministers to get on with the job, and by and large they succeeded.

It helped that he was blessed with some talented individuals, including Aneurin Bevan and Ernest Bevin - an advantage denied to some other PMs, including Edward Heath (13th) and, with some exceptions, Thatcher - but it was to Attlee's credit that he was able to get the best out of them.

He could also count on a healthy majority and a united party, at least for his first five years in office, unlike John Major (15th) or Ramsay MacDonald (14th), and had time to make his mark, unlike Alec Douglas-Home (19th).

This underlies how much prime ministers are at the mercy of what Harold Macmillan (5th) called "events, dear boy", as James Callaghan (12th), who took over amid a looming economic crisis, could testify. Even Churchill may have been ranked lower were it not for US and Russian intervention in the Second World War.

"The circumstances that people inherit and what they go on to do with them is crucial," says Dr Randall. "Whether the economy is doing poorly, or whether the international environment is unstable, and also whether they were able to win a significant majority and if they're able to govern without any party division."

It is also possible to have a glittering career blighted by one enormous mistake. Anthony Eden (20th and last) had been an exemplary foreign secretary, and had the credibility for having been one of the first outspoken opponents of appeasement, but his disastrous decision to invade Suez is the only thing anyone ever remembers about his premiership.

Blair's position in the poll may be a blow to the man who is said to have more than half an eye on his own place in history, but it is unlikely to climb much higher. However, he can lay claim to a creditable runners-up spot.

"Blair has got to go down as the second most successful Labour prime minister. He has achieved a significant amount and he has had two full terms and it looks like he will achieve a third, although it is unlikely he will serve it," says Dr Randall.

"His inheritance was a good one and it is an achievement to not mess things up, as other prime ministers have done, although he has divided his party, not only over Iraq but also private sector partnerships.

"But with any prime minister, particularly one who has had such a long run in power, they have normally made their significant achievements fairly early on."

While Blair's reputation may still be affected by comparisons with his successor, it is Attlee's style which provides a better model to follow, according to Dr Randall.

"There is perhaps an ideal there, and for me a concern with collective decision-making is a better way of governing, allowing people who have got their portfolios to pursue them, rather than exclusively prime ministerial decisions," he says.

But this is just one of the qualities we should look for in a prime minister, he adds, with the proviso that different circumstances may demand different approaches.

"They have got to have a relatively clear idea of what they want to make of the office and their time in government; they have got to be able to maintain support amongst their party, and they have also got to be seen to be fulfilling public aspirations," he says.

"They have got to have some stature on the international stage and some ability to represent their country, or at least have a very able foreign secretary.

"With Attlee it was a simpler age, and charisma was not a necessity, but now the criteria for prime ministers is you have got to be media savvy, which is why Major fared so poorly.

"Our expectations of prime ministers have changed, as well as what is expected from the job, and quite clearly no one individual is going to match up with all of them. Ultimately, people will look back at their records, at what they achieved and whether they were responsible for those things or not."