Industrial action "becoming increasingly routine" as figures show 1.4m days lost to unrest in 2011

There were 149 stoppages of work arising from labour disputes in total last year according to the figures, amounting to 1,389,700 lost working days. Of those disputes 61 were in the private sector and 88 in the public sector – almost double the number of public sector disputes in 2010. Over 1.5m workers were involved in disputes, almost 12 times as many as in the previous year and more even than the average number involved in industrial action in the 1980s.

Although skewed by the impact of last year's public sector pension strikes, the data shows that industrial action by workers is becoming "increasingly routine", according to employment law expert Christopher Mordue of Pinsent Masons, the law firm behind Out-Law.com. The "mass day of action" in November 2011 accounted for 90% of the time lost to strike action but only 2% of the stoppages, according to the data; with a particularly heavy impact on the education sector.

Mordue said that although the action represented an "acute high water mark" in the impact of industrial disputes which had "not been replicated since by anything on the same scale", the data showed that strikes were in no way confined to the public sector.

"Strike action in the private sector also increased in 2011, with the construction sector being particularly affected through a wave of strikes over redundancies," he said. "This trend has continued into 2010 – data for the first six months of 2012 suggests that this year will see a higher number of private sector strikes than in 2009 and 2010, with the number of strikes in public and private sectors being broadly equivalent," he said.

However, the number of days lost as a result of industrial action in the private sector tended to be "proportionately far less" than in the public sector, he said, perhaps because of "a greater reluctance by private sector workers to lose pay through industrial action" and less influence from large trade unions than in the public sector.

According to the ONS' figures, a period of what appeared to be a more constructive and cooperative relationship between unions and employers following the credit crunch in 2008 has given way to an increasing number of ballots for strike action over pay or pensions. 95% of working days lost and 48% of stoppages were due to disputes over pay, with a further 36% of stoppages a result of disputes over possible redundancies.

Mordue said that the figures pointed towards longer term deterioration in relations between employers, employees and trade unions as companies' economic troubles continued.

"The credit crunch seemed to create a more constructive relationship between unions and private sector employers - in particular, many employers were able to strike agreements with unions for temporary shut-downs and shorter working weeks," he said. "That tide seems to have turned during recent years of austerity and recession, with unions increasingly calling strike ballots over both pay and redundancies. Employers – whether public or private – need to recognise that strikes are increasingly routine and ensure that they have robust contingency plans in place to maintain business continuity and limit the impact of industrial action."

Employment expert Katie Douglas of Pinsent Masons said that there had been a "marked rise" in private sector employers seeking advice as a result of actual and threatened industrial action over the past couple of years. She added that there was a "definite and worrying trend" for employees and trade unions to respond to disagreements, for example over pay or redundancies, "as a matter of course", even in cases where the offers made by employers were "very reasonable in the current economic climate".

The law surrounding industrial action is extremely complicated, she said. However, she noted that recent case law developments had made it harder for employers to obtain injunctions to prevent strikes from taking place.

"Recently, the courts have been more lenient in relation to mistakes made by trade unions during the balloting process," she said. "This has allowed industrial action to proceed as lawful, despite some relatively significant procedural failures by the relevant union when carrying out the ballot."

When UNISON balloted its members on their participation in the public sector 'day of action' last year, Christopher Mordue told Out-Law.com that an error in the ballot notification sent to employers by the union could have left the vote open to legal challenge. Aggregated ballots, in which the votes from members from a number of employers are all counted together, are not in themselves illegal where a valid trade dispute affects a union's members within each employer. However, unions must satisfy complex rules before such a vote can be conducted.