Regional brewer Greene King has officially christened a third vat for its unique Old 5X ale, believed to be the only beer in Britain still matured for two years before being released for sale.

Old 5X, a 12% ABV brew is stored in oak vats and then blended with a weaker brew, BPA, to make Strong Suffolk Vintage Ale, Greene King's award-winning limited-availability bottled ale.

However, the company only had two 100-barrel vats, each 120 years old, for maturing 5X, and it was having to tell its salesmen, who were getting more and more orders for Strong Suffolk, that they could not have the beer for another 12 months.

Greene King has now had a third vat built, eight feet high and weighting 2.4 tonnes, in its newly-opened museum at its brewery in Bury St Edmunds, Suffolk. Last week the vat was filled with 3,600 gallons of newly-brewed Old 5X in front of a crowd that included the mayor of Bury St Edmunds, who saw Greene King's brewing director, John Redmond, smash a bottle of Strong Suffolk over the vat to christen it.