By Evan Davis BBC Economics Editor

The annual Mansion House speech is a strange occasion.

It provides a blank sheet of paper for a Chancellor to say whatever he wants.

But last night, it felt a million miles from Clinton Mississippi, where scandal-ridden Worldcom is based, and indeed it felt a pretty long way from the modern dealing rooms of London where shares had taken a pounding earlier in the day.

Instead, it seemed almost a piece of well-timed escapism - a chance to dress up, eat well and listen to some after dinner speeches.

It was obvious that the Chancellor, plus the Lord Mayor and the Governor of the Bank of England (who both also get a chance to speak) had to do a bit of reassuring.

Don't overreact was the message of the Lord Mayor (although he had written his speech before the Worldcom affair broke).

Don't panic was the message of the Governor, interest rates will go up but not yet.

And cautious optimism was the message of the Chancellor - the fundamentals of the global economy appear sound.

Certainly, there was no panic in the air.

Euro debate

But for an occasion as full of ritual as this one, it was obvious that Gordon Brown would have to make extensive reference to the euro, and the five economic tests as to whether Britain should join.

It has become almost a tradition of the Mansion House speech that the Chancellor teases the audience with some well-chosen words that a) show he is pro-European b) re-affirm the five tests (and his control of them) and c) say little or nothing that an ordinary person could understand as an expression of opinion on the euro.

Because the press pack are not ordinary people, they spend the evening feverishly interpreting the Chancellor's words - "we're going in", "we're staying out", "we don't know".

Last night was no exception.

One third of the speech was on the subject of the euro,

The Chancellor gave a detailed exposition of what the five tests might involve.

It wasn't the first time we had an insight into the work the Treasury is doing on the five tests - in November, the Chancellor published a document outlining the technical work occurring behind the scenes - but this was the first time we had it in verbal form.

It was a heavy speech.

Reading between the lines

True to the ritual, the journalists tried to read into the words, a message of love or loathing for the single currency.

In my view, only the most clairvoyant could succeed.

The truth is that some of the questions the Chancellor raised (about the housing market for example, or the effect of the EU's Stability Pact on public investment) look designed to generate a negative answer to whether Britain should join.

The specific mention of the exchange rate may be designed to remind us that things are moving towards British convergence and entry.

The November document was rightly seen as a signal that passing the tests was no easy task.

Some of us jokingly started referring to the five tests as the five hurdles; but the speech last night added little to that document, and I rather doubt we were meant to be guided to a view one way or the other as to whether Britain joins.

The Chancellor was simply trying to tell us that the tests are substantial.

Which incidentally, he would tell us, whether they were or whether they were not. The whole ritual is getting a bit tired.

The only encouraging thing is that by next year's Mansion House speech, the teasing should be over, and we should have an actual statement from the Chancellor on whether Britain has passed the tests.

Roll on next year.