Mr Blair in "humble" mode is not always convincing. His performance yesterday, however, looked very much like the real thing.
The morning after the historic victory was attended by a conspicuous lack of triumphalism. Understandably so, as Labour's second landslide win and that great Commons majority, came on the back of the lowest election turnout since 1918.
Westminster's first-past-the-post, winner-takes-all system (which Mr Blair will be even more loath to change) may have justified Mr Peter Mandelson's boast that Labour was now established as the natural party of government. However, the governing party's 42 per cent share of Thursday's vote reflected the positive choice of a mere 25 per cent of the British electorate. The non-voting stay-at-home party - with 41 per cent - was the day's other big winner.
Presumably on the advice of the spin doctors, Mr Blair had ordered ministers to be modest as he prepared to face the country back in early May. But it assumed every appearance of reality as it became clear that, after four years in power, Labour had rather more to do than collect the plaudits of a grateful nation.
One of the defining moments of the otherwise stage-managed campaign came with Mr Blair's confrontation with Ms Sharron Storer over the state of the hospital treating her partner for cancer. From his pronouncements thereafter it became apparent that Mr Blair had got the message. The voters might still be prepared to trust the NHS and other public services to Labour - but they were not impressed with the government's performance to date.
Labour's manifesto cast "the project" as a work still in progress. This proved a mirror image of the public's perception. That was reflected, in turn, in the Prime Minister's sombre address to the nation outside 10 Downing Street yesterday.
If election night had provided Labour with a remarkable and truly historic victory, and a mandate for reform and investment, Mr Blair had no difficulty with the translation. "It is also very clearly an instruction to deliver," he declared, in an early warning to those hopefuls lining up for jobs in his new administration.
Earlier this week Mr Blair appeared cagey when pressed on his commitment to take health spending up to at least average European levels. The public expectation, however, is clear and sky high.
WHATEVER the truth about that £5 billion "black hole" in the Chancellor's spending plans, the view is also emerging that if they are to provide the health, education and transport services people want and believe they have been promised Labour may ultimately have to match European-type spending with European levels of taxation.
It is certainly hard to see Mr Blair's notax-hike compact with middle Britain standing the test of time. Likewise his relationship with the trade unions will be sorely tested over his plans for increasing private sector involvement in the public services. One consequence of his second big majority, as Mr Tony Benn has cheerfully predicted, is that the traditional left inside the parliamentary Labour Party may prove much less biddable.
Beyond the realm of domestic politics, Mr Blair's biggest challenge will be to win the debate over membership of the euro. His Downing Street address yesterday gave the clearest hint that he remains determined to do so. Britain and the British people, he said, were "very special". And their "very best" quality was their ability "when we need to do so, to face up to and overcome the challenge of change".
Against the backdrop of jittery markets, Mr Blair has set the scene for the promised great European debate. Yet again, he will have to make the political case to a sceptical public, and on the euro to do so against the threatened unremitting opposition of the Sun.
The 1997 parliament was marked by the longest political honeymoon in history. Mr Blair may savour the memory. Notwithstanding the collapse of the Tory Party, the honeymoon this time is likely to prove short-lived. And next time Labour will have to run against its own record.