In 1931, George Orwell – who made a cottage industry of slumming it and writing about his adventures – spent September picking hops.

For many centuries, poorer Londoners and those who relied on itinerant farm work made a habit of "hopping down in Kent", picking the hop vines which provided an essential ingredient for English beer. The kids came too and it was the nearest many families got to a summer holiday.

Orwell didn’t much like the experience.

"Hop-picking is far from being a holiday," he complained, "and, as far as wages go, no worse employment exists."

While he conceded there was a bucolic aspect to hopping, toiling amid "an unutterably refreshing scent, like a wind blowing from oceans of cool beer", the spiny stems of the vines cut into his hands, and the pay – based on the amount picked – was pitiful.

As a novice at the task, Orwell couldn’t manage to earn in a week more than nine shillings (45 pence – the equivalent today of £45). And dossing down on straw in pickers’ huts he described as "worse than a stable" wasn’t much too his taste either.

Ham & High: Hop picking at Yalding in Kent in 1944, taken for the Ministry of InformationHop picking at Yalding in Kent in 1944, taken for the Ministry of Information (Image: rights free)

But for East Enders, casual work which got you into the countryside for a few weeks, with free accommodation of sorts thrown in and earning enough to cover train fares, food and ample flagons of beer, was an attractive option. In the 1920s and ‘30s, tens of thousands of Londoners each year are estimated to have headed to the Kent hop gardens - there’s wonderful footage from that era on YouTube showing families of hop pickers at work.

Hops grow on stems which can be several metres long, and were trained on poles – hence The Hop Pole as a popular name for a pub. The stems were cut down and the cone-like hops, usually in clusters towards the top of the vine, plucked off by hand.

After the Second World War, mechanisation slowly superseded casual labour, and imported hops partly replaced home grown. The actor and singer David Essex – the son of a docker, born in 1947 and brought up in Canning Town – went hopping as a child.

"I saw stars for the first time, in skies clear from the obscuring murk of the industrial East End," he has recalled. But by the 1960s, the September hop-picking exodus was just about over.

The National Trust still has a working hop farm at Scotney Castle near Tunbridge Wells, complete with old hop pickers’ huts, though these days the hop vines are stripped mechanically.

Hops are one of those rare agricultural crops that you hardly ever see in supermarkets or greengrocers. Many might be unfamiliar even with what a hop looks like.

If so, take a turn down Hampstead High Street to a long lost brewery still seemingly adorned with splendid clusters of hop flowers (technically, strobiles or seed cones) albeit in stone rather than on the vine.

Ham & High: Brewery gateway in Hampstead High StreetBrewery gateway in Hampstead High Street (Image: Andrew Whitehead)

The entrance to what was Hampstead Brewery and is now Old Brewery Mews has some of the best ornamental hops around – at least, that’s what we think they are.

These certainly have the typically pine cone shape of the hop, but are in a sheaf as if a cereal crop. Perhaps the designer had only a passing familiarity with his subject.

Ham & High: Close up of hops on the brewery gatewayClose up of hops on the brewery gateway (Image: Andrew Whitehead)

As the inscription indicates, the first brewery on the site dates from 1720 but it was rebuilt in 1869 which is presumably when this impressive gateway was constructed. At first, the brewery simply supplied a few local pubs, including the adjoining King of Bohemia – a seventeenth century drinking place rebuilt in the 1930s which survived until as recently as 2003 (it’s now the Reiss fashion store).

By the late 19th century, Hampstead Brewery was on an altogether bigger scale. You can see on the bottom left of the Harris & Co advert the surviving gateway from Hampstead High Street leading into the substantial brewery premises.

The more imposing of the brewery buildings survive down the mews – they were converted initially to offices fifty years ago, a none-too-common adaptation of an industrial building for other use. The spectacular brewery chimney was unstable and pulled down. Much of the rest of the labyrinthine brewery site has been developed for residential use.

Hops are what makes a pint of best English bitter, well, bitter. Hop varieties such as Fuggles and Goldings were particularly sought after. The US is now the world’s leading hop grower; Britain barely makes the top ten – there’s 50-times more hops grown in Germany than in the UK.

But at least hops still have a place of honour on Hampstead High Street.

Andrew Whitehead is a historian and the author of the Curious series of books about localities in North London.

Ham & High: The old Hampstead BreweryThe old Hampstead Brewery (Image: Andrew Whitehead)