Spanish air-traffic controllers on Monday announced a second series of four strikes in protest at the failure to admit one man who was sacked following a strike in December and sanctions imposed on 61 others.

The strikes will be held between 10am and 1pm on July 11th and 25th and between 5-8pm on July 12th and 26th and are a continuation of the strikes held on 8th, 10th, 12th and 14th June.

The controllers' union USCA issued a statement calling the attitude of the employers to be "inadmissible," in respect of failing to lift the sanctions on the 62 workers, although they repeated their willingness to continue negotiating.

The strike which led to the disciplinary action was called with no warning on December 2010 bank holiday weekend, which is one of the weekends when most people in Spain travel by air in the entire year. It caused hundreds of flights to be cancelled and left mages of passengers stranded at airports all over Spain.

Such was the chaos that the government declared a state of emergency to allow military air-traffic controllers to be brought in to help get flights off the ground.

In contrast the strikes caused in June this year caused very little disruption given the 70 percent minimum service imposed by the Spanish Public Works Ministry and that percent will again be imposed in July to avoid disruption to holiday traffic.