LONDON - A British union whose members operate the immigration and arrivals service at airports are to go on strike on July 26, the day before the Olympic Games begins.Members of the Public and Commercial Services union (PCS) voted for a strike on July 26 at ports and airports across Britain.July 26 is expected to be one of the busiest days on record for Heathrow Airport, London’s principal airport and one of the busiest airports in the world, where most Olympics arrivals are made.The British Home Office deals with immigration, and a spokesman told Xinhua on Friday afternoon that the strike was "irresponsible”, and that they were open to talks with the PCS union to avert the strike."We’ve asked them to call the strike off. We are ready to engage with the unions, we are happy to work with them to get the strike called off. We think it is unacceptable that have called it on the eve of the Olympics for maximum disruption with no real mandate to do so,” the spokesman said.On a normal July day, Heathrow, which already operates at close to its capacity, would expect to handle 190,000 passengers. On July 26 it is expected a new record could be set with 249,000 passengers.A PCS spokesman told Xinhua that the strike was a long-running dispute over job cuts, pay and privatization.Pay has been frozen for two years, and the next increase will be 1 percent, below the current 2.4 percent inflation rate. The union is fighting 8,500 job cuts across the Home Office.About 16,000 PCS members took part in the ballot, with 57 percent voting for the strike.The PCS spokesman added that PCS members would also refuse to work overtime and would work to rule over the period from July 27 to Aug. 20, covering the entire Olympic Games period.He added, "If ministers continue to refuse to negotiate, the union will announce further action at a later date.”