Diageo is to close its Park Royal brewery in West London next summer and move its Guinness brewing operations to Dublin. The first Guinness was brewed at the site on 21 February 1936 and the brewery went on to supply much of the draught Guinness for the British market. At one time Harp lager was brewed at Park Royal and brewers at the site also pioneered the introduction of draught Guinness in 1961. Gerry O'Hagan, the supply director for Diageo's UK & Ireland brewing business said: "A major review of our brewing business in UK & Ireland has shown very clearly that the best option for the future would be to consolidate our production for the GB market into Ireland. "Our Dublin brewery already produces the equivalent of some eight million kegs of Guinness every year for distribution to international markets including Europe and the US. "With some additional investment in technology St James's Gate could absorb the four million equivalent kegs currently produced at Park Royal." Diageo said that it would now enter a full consultation process with the representatives of those Diageo employees at Park Royal. The move is expected to cost 90 jobs.