Which organisation has bombed the department store Harrods three times?

Explanation

Harrods is a famous London department store located in Brompton Road in Knightsbridge. Harrods founder Charles Henry Harrod first established his business in 1834. Back then, it was a wholesale grocery, but today the store covers an area of 92,000m² and has 5,000 employees. It is the biggest department store in London, and probably also in Europe. Since 1974, Harrods has been targeted by IRA bombs three times. In 1985, the business was bought by Mohamed Al Fayed whose son, Dodi al-Fayed was the boyfriend of Princess Diana.