A leaked report claimed the Spanish government plans to increase its stake in EADS, the European aerospace group which owns 80% of Airbus.

Union leaders have vowed to fight any moves and Airbus management say the report is "total speculation".

Mrs Gillan said: "Any complacency must not be allowed into the equation."

A leaked report claimed the Spanish government was interested in increasing its stake in EADS when UK defence and aerospace group BAE Systems said it would sell its own 20% stake in Airbus.

It sparked fears that the Spanish government wanted to move the production of the wings for the giant A380 plane to Spain from Broughton, where 7,000 workers are involved in their construction.

We certainly wouldn't sit back and let this happen Union spokesman Rob Dowie

Following a visit to the Broughton factory on Thursday, Conservative Mrs Gillan said: "It's an absolutely unique and an extremely exciting manufacturing project.

"We need to keep this type of capability in this country.

"We must always be on top of what's happening around the world."

She said she had been hugely impressed with the work at Broughton, and said she had been assured Airbus had "tremendous" orders on its books for the new A380 superjumbo.

She described the factory as a "world-beater" and said everything must be done to keep it in Flintshire.

Cheryl Gillan says Airbus must be retained in Flintshire

"This does show that we can never take for granted the employment prospects offered by Airbus," he said.

'Total speculation'

"I will be seeking assurances that the UK government will resist attempts by any Airbus partner to pull employment from the UK."

Unions at the Flintshire plant said they would fight any attempt to move wing production away from the UK.

Broughton works convenor Rob Dowie said any attempt to undermine wing-making at the factory would meet resistance.

He said: "We are here to protect the interests of our members and improve terms and conditions. We certainly wouldn't sit back and let this happen."

Mr Dowie said he was not surprised at the reports from Spain.

"When the A380 project was launched the Spanish prime minister indicated that they wanted to do something like this," he added.

A spokeswoman for Airbus at Broughton dismissed any plans to move production to Spain as "total speculation".

She added: "We have received assurances from EADS regarding its full and long-term commitment to Airbus in the UK, and to its workforce, should there be a change in shareholders' structure."