British Airways (BA) said Friday it feared 'massive disruption' from threatened strikes by cabin crews later this month as Prime Minister Gordon Brown called for a last-ditch negotiated settlement between the airline and trade unions.

'We certainly hope that a negotiation is reached so that people don't need to go on strike,' said a spokeswoman for Brown shortly after two sets of strikes were announced by the Unite trade union for the end of March.

Unite, which represents some 13,000 cabin staff at BA, said members would be called out for three days from March 20, and for a further four days from March 27. It has ruled out strikes over the busy Easter weekend in early April.

Len McCluskey, Unite's assistant general secretary, accused BA management of turning down a 'remarkable' offer from the union that would have 'given the airline everything it wanted'.

The offer was understood to have centred on a one-year pay freeze for cabin staff, followed by a 2.6-per cent pay cut that would have saved BA more than 60 million pounds a year.

BA chief executive Willie Walsh said he was 'extremely disappointed' at Unite's decision for which there was 'absolutely no justification.'

However, he would ensure that disruption was kept to a minimum and also remained open for talks 'any time'.

'Everybody knows this is a trade union that wants to destroy BA. This is about securing the future of a great British brand,' said Walsh.

Meanwhile, McCluskey accused BA of 'bullying' and 'intimidating' the unions during the negotiations. He said BA's efforts to recruit a 'strike-breaking army' would not save it from a 'devastating' dispute.

Walsh said the airline had 'robust contingency plans' in place that would allow it to operate a substantial part of its long-and short haul services.

BA said it has recruited more than 1,000 'volunteer staff' to work as cabin crew and would hire 23 fully-crewed planes from charter companies to fill the gaps.

The long-running dispute between BA management and cabin staff - which forms the largest single section of employees within BA - has centred on cost-cutting measures at the debt-ridden airline.

Unite, while insisting that it recognised BA's 'difficulties' and was prepared to back saving measures, said its highly-trained members had been angered by BA's unilateral move to cut cabin staff on long-haul flights by one - a decision BA has refused to reverse.

However, industry analysts said that unions feared that BA would, in the longer term, use changes in contracts to hire 'cheaper staff'.

BA made record losses of 410 million pounds in 2008, followed by a record half-yearly loss of 292 million pounds in the first six months of 2009. It has been weighed down in particular by a massive pension deficit of 3.7 billion pounds.

In a merger agreement signed with Spain's Iberia last November, the Spanish carrier reserved the right to terminate the deal if BA should fail to tackle the pension deficit.