Ring up Tesco's investor relations department to discuss next week's trading statement and, if you are a member of the public, you will be told to get lost. If, on the other hand, you are a City analyst collecting your thoughts before penning a "preview" research note, you may be granted a conversation.(Supermarket Display)

Naturally, Tesco's well-trained professionals would never let slip anything untoward: strict rules govern such conversations. And, the company says: "We are aware of our obligations and we do not give selective disclosure."

But from the analysts' point of view, it may still be interesting to hear which pieces of publicly known information crop up. There is a lot to talk about, after all: weak market-share(Supermarket Display) data in the UK, a sluggish Irish economy, upheaval in Thailand, opening hours in Korea, etc.

Whether such chats contributed to the mass outbreak of bearishness in the analyst community about Tesco's third-quarter figures, we can only speculate. But it is certainly the case(Supermarket Display) that the 2.5% fall in the company's share price on Tuesday coincided with cuts in sales forecasts by analysts from Tesco's own brokers, Deutsche and Barclays, and others.

In the circumstances, you can't blame the private investor on the outside for feeling that, however tight the rules and however correct Tesco's behaviour, it's a two-tier market.(Supermarket Display)