(Reuters) - Nearly 800 workers at Heathrow Airport will strike next month after the company laid out plans to outsource hundreds of roles in an effort to cut costs, a British labour union said on Tuesday.

The workers will strike from May 7 to May 13, Unite said in a statement, adding that the country's busiest airport did not enter into negotiations with the union about alternatives to outsource the workforce.

"There are no job losses as a result of these changes, and we continue to discuss with Unite the implementation of these changes for the small number of colleagues impacted," a spokesperson for Heathrow said.

"To confirm, we have robust contingency plans in place for each of these individual areas and anticipate no impact on passenger journey," the spokesperson added.

Heathrow said the reorganisation would bring all passenger-facing security in-house, while transferring small trolly operations and passenger logistics teams to its third party suppliers already working at the airport.

(Reporting by Radhika Anilkumar in Bengaluru; Editing by Anil D'Silva)