Pictured above: Karen Macpherson

We could be entering a new age of industrial strife, a leading employment lawyer has claimed.

And Karen Macpherson, employment partner at the Birmingham office of DLA Piper, warned that unions were getting smarter in their international links.

Speaking as the British Airways cabin crew strikes dominate the headlines, she cautioned: "It really opens the gates for potential long term chaos at our airports.

"And, with a number of other unions flexing their muscles for possible action, the fear is that we may be headed for a troubled industrial relations period.

"This often happens after recessions have forced job losses and pay cuts. Once better times materialise, the dam of frustration that has built up suddenly bursts.

"Let's hope this does not happen again for the sake of industrial relations and the future of the economy, but the signs are ominous.

"And if a Conservative administration gets in at the coming General Election, imposing tough pay restrictions on the public sector, things might just get worse before they get better."

Highlighting the cross border links between unions, Ms Macpherson continued: "Trade unions across the world were flashing up on the radar in support of the striking British Airways cabin crew to the dismay of the airline's management and passengers. "Unions in over 120 countries representing various aviation roles including cabin crew, pilots, ground staff, baggage handlers and air traffic controllers claimed to be ready to support the BA strikers. This is clear evidence of the increasing globalisation of trade unions.

"In recent years unions have been seeking to extend their international reach to apply pressure to more susceptible parts of an international business, targeting specific domestic operations and also 'exporting' industrial disputes.

"While in the UK and Australia 'sympathy strikes' are illegal and can be squashed with an injunction from the relevant court or industrial tribunal, other countries allow solidarity action. And the TWU in Australia were citing health and safety concerns for their workers in servicing BA planes that could be staffed with inexperienced, untrained and unskilled strike breakers."

The Unite union has confirmed that it will not strike over Easter, but warned there could be further action after April 14 if a resolution has not been agreed. 

Ms Macpherson noted: "The terms of the ballot taken by the union allow them to opt for further action at any time as long as it relates to the same dispute. So unless a resolution is reached, we could see further disruption in the coming months and even into the summer. 

As to the conduct of the dispute, she said BA could lawfully discipline and sack staff for bullying and harassment, but if the reason for the action was their role as trade union officials during a strike, that could lead to an "automatic unfair dismissal case".

The distinction between official and unofficial industrial action is key. An employee who is involved in industrial action will usually be in breach of their employment contract and the employer may be able to deduct pay or dismiss them. However, if the industrial action is 'official', the participating employees have some protection against dismissal.

There is no specific legal restriction on an employer using temporary agency workers to cover for striking workers. There are, however, legal restrictions on the agency which supplies the workers. Nevertheless there is nothing to stop an organisation hiring fixed term employees directly to cover for striking workers.