AIR links between Scotland and Heathrow provided by bmi will be lost unless a £172 million buyout is given the go-ahead, the head of British Airways's parent company has claimed.

Addressing business leaders in Glasgow, International Airlines Group (IAG) chief executive Willie Walsh said politicians had "not understood" the risks involved in allowing bmi to collapse. He said it was only still operating due to £60m provided by BA to see it through to the end of March.

The alternative to the deal, he argued, was for bmi to collapse and for its valuable Heathrow landing slots to be sold off to international airlines, which would be unlikely to fly domestic routes to Scotland.

That scenario would also threaten BA's existing domestic services to Scotland, as it would increase pressure to use those slots at Heathrow for more lucrative long-haul flights.

At a talk organised by the Glasgow Chamber of Commerce, Mr Walsh said: "I would encourage politicians to under- stand the risk involved in this deal not going through.

"I don't think people fully appreciate the only reason bmi continues to fly today is because BA has given assistance of £60m in anticipation of getting competition clearance.

"The only reason those services will exist in the future is that those services you're worried about in Scotland are core to our business model, and the evidence is the fact we fly so many flights from Heathrow to Scotland."

The European Commission is looking at the purchase of bmi, owned by German airline Lufthansa, by IAG, formed by the merger of British Airways and Spanish airline Iberia. It is expected to rule by March 16.

Mr Walsh met Scotland's Transport Minister Keith Brown on Wednesday over fears expressed by business leaders and politicians that handing BA an effective monopoly on Heathrow services to and from Aberdeen and Edinburgh would lead to price rises and service cuts.

While conceding a minority of bmi's Heathrow landing slots used for Scottish services could be converted for long-haul routes, he said the airline would continue to provide a robust service to Scotland.

He also hit out at claims by Virgin Atlantic, his main rival to buy bmi, that the deal would be bad for Scottish passengers.

He said: "Virgin Atlantic has never shown any interest in domestic flying and I don't believe it would operate domestic flights.

"Virgin already has more slots than it uses and rather than operate those slots to Scotland, it leases them to other airlines.

"It has had the ability, well within its resources, to fly to Scotland and it's never done so or shown any interest in doing so."

The takeover would create at least 50 high-paid engineering jobs in Glasgow as the maintenance of bmi's 25 short-haul aircraft would be transferred from overseas to BA's maintenance depot at Glasgow Airport, which currently employs 300 people servicing the BA fleet, Mr Walsh said.

Mr Walsh also disputed claims by Virgin Atlantic that BA had put up fares between Glasgow and Heathrow by 34% after bmi withdrew from the route last March, saying the figures did not include online bookings.

His assurances were welcomed by Stuart Patrick, chief executive of Glasgow Chamber of Commerce, though he said he would still press BA to increase the capacity on services between Glasgow and Heathrow.

Mr Walsh's claims were denied by Virgin Atlantic. A spokeswoman said: "Our bid would have resulted in the maintenance of bmi's existing routes from Heathrow to Scotland."

A Transport Scotland spokesman said: "BA/IAG were only able to give a commitment to maintain the current service levels in the short term, however [Mr Brown] welcomed [Mr Walsh's] assurance that they remain committed to Scotland. We were also assured that job losses, if any, would be kept to a minimum."