The Government is now involved in a damaging row with the country’s biggest union after a cabinet minister launched an extraordinary attack against a planned strike by British Airways cabin crew.

Transport Secretary Lord Adonis said the planned seven days of industrial action could put the future of the airline at risk, calling the walkouts “totally unjustified.”

Unite hit back at the minister, saying he was “badly informed” about the long-running dispute, adding that he should be urging the airline to reinstate an offer it withdrew last week.

It is understood that the union has made representations to 10 Downing Street about the minister’s intervention, and it is now expected that the Prime Minister will directly intervene.

Lord Adonis appealed to Unite to return to the negotiating table in an attempt to avert the industrial action planned to begin with a three day strike from next Saturday, followed by a four day stoppage from the following weekend.

Lord Adonis told BBC1’s Andrew Marr show:

“The impact this will have will not only be deeply damaging on passengers, it will … threaten the very existence of British Airways.

“The stakes are incredibly high in this strike. I absolutely deplore the strike, it is not only the damage it is going to do passengers and the inconvenience it’s going to cause – which is quite disproportionate to the issues at stake – but also the threat it poses to the future of one of our great companies in this country.

“It’s totally unjustified, the strike, on the merits of the issues at stake. I do call on the union to engage constructively with the company at this late stage.”

A Unite spokesman said:

“Lord Adonis appears badly informed. We all want to avoid strike action and Unite is always ready to negotiate. Unite was preparing to put BA’s offer to our members. Had they accepted it, there would be no strikes.

Unite is a major Labour Party donor and critics have claimed the Government is unwilling to condemn the union’s actions.

Liberal Democrat Shadow Transport Secretary, Norman Baker said:

“BA and the Unite union are behaving like spoilt children in the playground and as usual it is innocent passengers who will suffer. They should call off their strike immediately and find some other way to make their point.

“The fact this strike is due to occur at roughly the same time as the Network Rail dispute looks suspiciously like co-ordinated union action. The unions are trying their best to wind the clock back to the 1970s and create a Spring of Discontent.

“The consequences for the Labour Party will be the same as they were in 1979.”