The union said the action, which will involve more than 2,000 members of security staff at Heathrow, would likely get under way in mid-June and run through to the August bank holiday weekend.
Unite had intended to serve Heathrow strike notice late last week, but will now do so this week, a spokesperson confirmed to TTG. The exact number of strike days and their exact dates is yet to be confirmed, although Unite last week indicated the action could run to more than 30 days.