It was a moral injunction that always was going to be hard to honour. And so it has proved. The newspapers have been full of stories. The Lord Chancellor's new wallpaper. The VIP lounge at Heathrow. The grace and favour homes. The Downing Street parties. The Blairs' new kitchen. The fleet of political advisers. The foreign trips for ministers' girlfriends.
As it happens, the new Government has been neither extravagant nor wasteful. Ministers hold important executive jobs and should be treated as important executives, not as Franciscans or Poor Clares. But the stories are damaging for two reasons. One is the dissonance with the faintly Gandhian tone of Mr Blair's sermon to new MPs in Church House, which implied that the Cabinet would shortly give away all worldly goods and hold everything in common.
The other, more important reason is that the new Government's media relations have been handled surprisingly badly. The slickest and sharpest campaigning machine in opposition has found it harder than expected to adjust to the quite different requirements of office. Part of the problem is that the previous government ended up with such a universally bad press that Labour, by default, had a soft ride. Now, whenever a story is written in a way not prescribed by the physicians of spin, the reaction is one of unbridled fury.
Lord Irvine's prickly and rather disingenuous defence of his pounds 650,000 refurbishment made a trivial issue memorable. Robin Cook's indignation when asked questions he does not like has been similarly counterproductive. It may be that he does not think the voters are concerned about (as opposed to vaguely interested in) his secretarial arrangements or frankly prissy distinctions between married and non-married partners. And he may be right, but that it not the point.
The spin-doctors have the same problem with questions they do not like. The letter written to the editor of the Today programme last month, complaining that John Humphrys had dared to repeat a question when he did not think Harriet Harman had answered it, was the prime example. Labour threatened to break off all diplomatic relations unless Today toed the line. The publication of the letter made the Government look foolish. But not, it seems, foolish enough. The batter-the-messenger culture seems to be alive and well.
Earlier this month, The Independent's Tokyo correspondent asked how the allegedly "new" apology that Tony Blair had gained from the Japanese prime minister on behalf of British former prisoners of war was different from an apology expressed two years ago, which Labour had described as unsatisfactory. Mr Blair's spokesman refused to offer any straightforward answer. Instead, he complained loudly about "clever wankers". It is, to put it mildly, an unfortunate way of handling questions, whether or not they are - as this one patently was - justified.
The first rule of good PR for governments must be to take the high moral ground and stick to it. The other nine rules were set out a few years ago by Christopher Meyer, who later became John Major's former spokesman and is now British ambassador to Washington. He wrote Ten Commandments for government spokesmen.
"Give the best and most detailed guidance possible," was one. Another was: "Do not lie. If you do, or knowingly give a wrong steer, the chances are that you will be found out and your credibility destroyed for good." Above all, he argued: "Do not waste time remonstrating with reporters when they have failed to write it as you would have wished. Only gross acts of bad faith, inaccuracy and unfairness merit a complaint."
Mr Meyer's commandments were widely welcomed when they were published in 1994. Among the many journalists who found warm words for them was a newspaper columnist who offered some more rules of his own. The first was: "You are only as good as your product. As they say where you've just come from: `You can't make s**t shine.'" In other words: if journalists are writing critical things, maybe that it is because there are things to criticise. If you have a good product to sell, don't worry: you will be able to sell it.
We say: hear, hear. Congratulations to the author - one Alastair Campbell, now press secretary to the Prime Minister. If ministers and their press secretaries had more confidence in their product, they might show less arrogance in its presentation. And they would not face such a relentless rain of stories about ministers enjoying the perks of office.
The aggression and indignation of opposition needs to be replaced by a consistent posture as the servants of the people. Snarling at William Hague across the despatch box, defending every charge on the grounds that "your lot did it too", is not humble enough. As Mr Blair himself warned his new covenanters six days after the landslide, if they forget that they are the people's servants, "the people will soon show that what the electorate give, the electorate can take away".