The Panel, which polices bids, also confirmed yesterday that BZW had been permanently barred from receiving a pounds 250,000 "performance" fee for its work for Northern.
It was BZW's failure to disclose the fee to the Panel last week when it bought a 2.3 per cent stake in the company which led to the offer deadline being extended, during which time the result shifted in favour of the bidder, US-owned CE Electric.
Alistair Defriez, director-general of the Takeover Panel, said: "It does raise the issue of whether the market should be fettered in some way. Some people feel this should be banned, and though this is not the view that has been taken here over many years, we have to review that."
Several big City investment institutions are thought to have made representations to the Panel, urging that share purchases by brokers should be banned altogether in the light of the Northern-BZW affair. Mr Defriez continued: "It doesn't happen more than two or three times a year. But we've seen in this case how critical it was. It was the swing factor."
CE Electric, controlled by US power generator CalEnergy, won the pounds 782m bid by the tightest of margins, with 50.3 per cent of Northern shares amassed by lunchtime on Christmas Eve.
Had the Panel not extended the deadline from the previous Friday CalEnergy would have lost, with 49.77 per cent of shares then under its control.
The Panel has rebuked BZW for not disclosing the "performance" fee when it asked for permission to buy Northern shares on Wednesday 18 December. The executive had agreed to the move on the basis BZW would receive only a flat-rate fee for its services, believed to be some pounds 1.5m.
Though the share-buying was a clear boost for Northern's defence, BZW has insisted that it was carried out without the prior knowledge of the com-pany and that the additional "performance" fee was in no way related to the outcome of the bid.
However, Mr Defriez said yesterday that BZW would never be paid the pounds 250,000 fee, which had been frozen pending the outcome of Northern's unsuccessful appeal against the deadline extension.
"I think you can take it that they won't receive that fee at all."
Asked whether this amounted to a fine by the Panel against BZW for its failure to disclose the fee arrangement, Mr Defriez said: "I think this is best regarded as a very controversial matter indeed. We felt it appropriate it should have no part in the bid arrangement.I wouldn't use the word fine."
BZW faces a separate Panel investigation into the affair which is likely to continue for several weeks. In the worst case, Mr Defriez said, this could hypothetically lead to the case being passed to the City watchdog, the Securities and Futures Authority. Another possible sanction could be a public rebuke by the Panel itself.
He also defended the role played by the Takeover Panel, which has been criticised for being too weak and too closely linked to the City institutions involved. Mr Defriez insisted punishments available to the Panel were tougher than critics realised.
"Criticising people can damage their reputations and their business. But if we were to find that something has arisen which merited a stronger sanction then clearly there are stronger sanctions available."
Meanwhile the board of Northern Electric has still not advised shareholders to accept CE Electric's 650p-a-share offer, despite having lost the takeover bid.
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