A strike by 9,000 British Airways ground staff could cripple summer services to Bermuda.

The grim news came after the British Transport and General Workers' Union warned they could ground the airline over plans to contract out more in-flight catering.

Now the workers will hold a strike ballot -- adding to the troubles of the airline, which is already facing a separate strike vote by cabin crew over pay.

The Transport and General Workers Union said results of the vote will be revealed on June 30, three days after the union announces the outcome of a strike vote by 8,500 cabin crew members embroiled in the pay row.

The unions insists it could cripple British Airways as it heads into the peak summer season. But the airline said it has contingency plans that would let it operate through a strike.

An airline spokesman in London called the latest strike threat unjustified and warned that the baggage handlers, catering staff and check-in workers at London's Heathrow and Gatwick Airports -- where Bermuda flights start -- could lose their jobs if they walk out.

British Airways already contracts out much of its catering and says it needs to find contractors for the rest of the work because it cannot compete with specialists in the business.

The airline view was backed by the Bermuda office of Britain's national carrier, which operates three services a week to Bermuda.

A spokeswoman for BA Bermuda said: "There is no strike at the moment and it's business as usual.'' She echoed that contingency plans to keep the fleet airborne were in place -- but declined to discuss them.

But is understood airline services would be badly affected by one or more strikes -- inevitably leading to cancellations.

The spokeswoman added: "There is no justification for this action by the TGWU. We have to call into question whether it's the action of a totally modern trade union.'' But she said: "We have high hopes that this will be settled -- we're just going to have to wait and see. I think it's a little to early to worry about cancellations.'' The spokeswoman claimed that in-house catering could not compete on cost with global enterprises set up many airlines and BA was unusual in having any catering as part of their organisation.

She said: "We have to be cost effective and we are making sure there are going to be no job losses within our catering operation.'' Tourism Minister David Dodwell said a BA strike would be disappointing -- but not necessarily catastrophic.

He pointed out that between 30 and 35 percent of travellers from the UK and Europe arrived via North America.

Through the end of April, 5,408 people or 6.4 percent of total visitors had visited the Island from Britain.

Mr. Dodwell said: "British Airways is clearly the major source of seats from the UK.'' He added that tour operators from Europe and Britain also tended to use London flights provided by BA.

Mr. Dodwell said: "Any strike would be disappointing, but it's far too early to tell if that will actually happen.

Transport Minister Wayne Furbert said any disruption to services to the Island would damage tourism -- and airport operations due to a drop in landing fees.

He added: "It would definitely affect tourism because we get a lot of business from people flying in and out of Britain.'' But he predicted the impact would be lessened by people using other carriers, although they would have to suffer the added inconvenience of flying to the US first.

Mr. Furbert added: "A lengthy strike would certainly not be in our interests because we would lose money from landing fees. We would look to see this resolved very soon.''