Paul Murphy, secretary of state for Wales, called Broughton's Airbus factory "the most important manufacturing facility in Wales" during a visit yesterday.

And he pledged to fight to save an £18bn tanker deal with the US Air Force, which would safeguard thousands of skilled jobs at the wing-making plant for a generation.

Speaking at the Airbus plant, he called for "fair play" over the US deal, which looked to have been won by Airbus earlier in the year but has since been re-opened to allow its American rivals Boeing to bid.

Mr Murphy told the Leader: "It is important for us to retain pressure on the US and I know that, for example, the British Embassy in Washington has got involved and is doing what it can to make sure fair play is had.

"We need a level playing field in terms of competition and from our point of view, we need to ensure fair play is had.

"I have discussed the matter with Brian Fleet (senior vice president of Airbus UK) and I have assured him we are 100 per cent behind him.

"This plant is hugely important for North Wales but also for the UK as a whole. It is the single most important manufacturing facility in Wales and is vital economically, industrially and socially."

About 7,000 people work at the Broughton plant, making it the single biggest employer in North Wales. The plant makes wings for a range of aircraft including the world's largest passenger plane, the A380 superjumbo.

The plant's future seemed to have been secured earlier this year when Airbus' parent company EADS was awarded the lucrative contract to replace the US Air Force's fleet of refuelling tankers.

But the deal is now hanging in the balance, after the US government decided to uphold a protest by Boeing over the deal.

Bidding has now been re-opened, raising fears among Airbus chiefs that the planemaker could lose out to its American rivals.

Mr Murphy praised Alyn and Deeside MP Mark Tami, saying he is playing a "seminal role" in the fight to safeguard the deal.

Mr Tami, who has received a letter from Gordon Brown in which the PM pledges his support for Airbus, said: "Our bid was the best from the beginning and the skilled workers at Broughton deserve that recognition."

After taking a tour, Welsh secretary Mr Murphy praised the ongoing expansion and innovation at the site.

He said: "I last came here in 2001 but a lot has changed. I'm always staggered by the sheer size of everything, from the machinery to the amount of people that work here."