The owners of Belfast International Airport have warned that the decision by British Midland bmi to transfer all its services to a rival airport in Northern Ireland could wipe £6 million sterling (€9.7 million) off its profits.

TBI published its latest trading figures for the first three months of the current financial year yesterday which it said were in line with expectations.

The greatest growth for the British airports group in the first quarter of this year came from Belfast International Airport, which saw passenger numbers grow by 15 per cent.

Last year 3.1 million people flew in and out of the international airport but some 28 per cent, nearly 700,000 of these air travellers were British Midland bmi customers.

British Midland announced last week that it plans to transfer all its services between Northern Ireland and London Heathrow and East Midlands airport to Belfast City Airport from October.

TBI yesterday revealed that the loss of British Midland to Belfast City Airport would wipe £2 million sterling of its pre-tax profits this year and an estimated £6 million sterling off pre-tax profits in the next full year to March 2003.

Despite a long-running dispute over landing fee charges, the airport group said it was surprised by British Midland's decision.

"We will now take aggressive action to restore the level of profitability to which Belfast International has grown, and a number of initiatives have already begun," TBI said.

The group said Belfast's improved profitability was due to increased passenger numbers - in part from new routes from low-cost operators such as easyJet - and improved retail outlets.

But financial markets and industry analysts have greeted the move by bmi with dismay. Many brokers downgraded their recommendation while the group's share price headed south to close on the London Stock Exchange yesterday down more than 18 per cent at 63.25 pence sterling.