Vulnerable small firms
There are two ways of looking at Tesco's figures this morning: as a bit worse than some of its close competitors, particularly those perceived to offer better value for money; and massively better than most retailers.
Tesco is far too big to be dismissed as an interesting exception. Its sales in the UK alone (and it has big overseas operations) are over £40bn.
So it matters - and not just to Tesco's shareholders - that in the seven weeks to 10 January Tesco's like-for-like sales (or sales per unit of selling space) were 3.5% higher than in the previous year.
And the resilience of Tesco's sales extended wider than relatively recession-proof food. Tesco says this morning that non-food sales rose a bit - and that it captured market share in electricals, clothing and entertainment.
That said, Tesco's performance appears to have been less robust than its closest competitors, Sainsbury, Asda and Morrison. And smaller retailers that position themselves as offering the cheapest food around, such as Aldi, have enjoyed much stronger sales increments (this morning's FT says Aldi sales rose 22.2% in December).
But Tesco is incomparably bigger than all of them. Aldi's UK sales are almost the equivalent of a rounding error in Tesco's profit-and-loss account. Tesco is as big as Sainsbury and Asda combined.
So it would be unrealistic to assume that Tesco could escape unscathed from the end of the longest, strongest consumer boom in British history.
But nor are its figures exactly consistent with the screaming headline this morning from the British Retail Consortium, which says "Worst December in survey's history" when summarising its members' trading performance in December.
The store groups that belong to the BRC suffered a 1.4% drop in total sales in December and a 3.3% fall in like-for-like sales.
Meanwhile the British Chambers of Commerce, representing a much wider range of businesses - some 6,000 of them - says that its survey of economic conditions in the last three months of 2008 discloses "a frightening deterioration" in the health of the British economy.
The BCC says that domestic demand is collapsing, exports are falling and confidence is through the floor.
So who do we believe, Tesco - which talks of a "steady UK performance - or the BCC and the BRC?
To reiterate, it would be wrong to dismiss Tesco as just one firm. In the UK alone it employs more than 280,000 people - compared with 680,000 people for all BCC members.
However, although Tesco, the BCC and the BRC may seem to be saying contradictory things, they are all telling the truth.
Tesco does have the advantage of being in food, which we have to buy even when the economic going gets tough. But it has two other enormous advantages.
It has a massive and fantastically strong balance sheet - so it is not constrained by the shortage of credit that's mullering smaller businesses.
And as a business it's so big that it can cut prices to win customers, and then share the pain of those lower prices with suppliers.
In other words, the most exposed business right now are smaller ones, with limited buying power and a dependence on credit that's harder and more expensive to maintain.
Some of these will fail because they borrowed imprudently during the boom years, or because they are badly managed or because they are in industries or markets in terminal decline.
Although there is a human cost to such failures, we shouldn't weep too much or try to prop them up. The fastest route to long-term economic decline is to put lame ducks on life support.
What should worry us however is that many fundamentally sound companies may fail, simply because some international banks have massively reduced their presence in the UK corporate-lending market and British banks have perhaps become excessively averse to taking risks.
These vicious trends have been conspicuous for months. And, after months of evaluating how to maximise the therapeutic bang for the taxpayers' buck, the government will tomorrow unveil measures that it hopes will correct some of those market failures.
To state the bloomin' obvious, even Tesco couldn't thrive if the productive capacity of Britain's small and medium sized firms were wiped out in the coming months.