The beer, Imperial Porter, is brewed locally from English hops grown in the Market Hall irrigated with rainwater and using leftover coffee grounds as mulch, and flavoured with coffee from Change Please and chocolate from Rabot 1745, both Borough Market traders.

Porter was first brewed in London in the early 18th century, and the name is thought to stem from its popularity with street and river porters, making it an appropriate brew for the market which originated on the banks of the river Thames over 1,000 years ago.

The star ingredient of the porter is the traditional variety of English hop known as 'Fuggles', originally cultivated in Kent by Richard Fuggles in the late 19th Century.

Grown in the Market Hall by Borough Market's urban gardening team, the hops are renowned for displaying delicate but complex flavours of mint, tea and marmalade.

Most hops used in the beer industry are kiln dried within 24 hours to preserve them, which can adversely impact taste. By using local brewers, Tap East, Borough Market could deliver the hops in their wet, fresh state within hours of harvesting; contributing to the beer's authentic flavour. Beers created in this way can only be made once a year, making them one of the world's most sort-after seasonal products.

The #LoveBorough Imperial Porter is the third brew from Borough Market's own hops, and has been curated by brewer Dan Tapper. The Imperial Porter is made from six malt varieties, heated to extremely high temperatures to produce the dark liquid.

The 85 % cocoa chocolate used in the beer is famed for its robust notes of oak and leather and was sourced by Rabot 1745 from a 250 year-old cocoa plantation on St Lucia. The coffee from Change Please was specifically chosen for its vibrant flavours of raspberry and blackcurrant.

The beer has been produced in collaboration with Tap East, a microbrewery in Stratford, East London whose founders have been trading at Borough Market for more than 15 years through specialist beer shop Utobeer and bar, The Rake.

Limited edition bottles of the 7.2% beer will be priced at £3.90 with £2 from each bottle going to the trader support fund. Bottles will be on sale from the Borough Market office, and from the merchandise stand in the middle of the market. The #LoveBorough Imperial Porter will also be exclusively available in the Market on draught from The Globe Tavern and The Rake.

Dan Tapper, expert brewer said: "As both a brewer and a food writer it has been an absolute honour to create a beer that not only displays genuine London terroir but also showcases some of Borough Market's most flavoursome produce.

"It hasn't been easy; the project took six months to realise with the help of coffee roasters, chocolate makers, brewers and urban gardeners but we're all thrilled with the final beer and are delighted that proceeds will be donated to Borough Market traders."

Darren Henaghan, managing director, Borough Market said: "We're proud to produce a sustainable and low-waste beer which is grown from hops planted right here in our Market Hall. Our urban gardening team used leftover coffee grounds as a mulch and rainwater to grow the English hops, and by using high-quality ingredients from our traders to flavour the porter, the result is a proper London brew."

Borough has long been synonymous with food markets and as far back as 1014. London Bridge attracted traders selling grain, fish, vegetables and livestock. In the 13th century traders were relocated to what is now Borough High Street and a market has existed there ever since.

Borough Market is fully independent, owned by a charitable trust and run by a board of volunteer trustees. The trust regularly run community events, free cookery demonstrations and support local community projects and schemes.

http://boroughmarket.org.uk