It is known as the quintessential British drink, but the volume of tea sold in the United Kingdom continues to drop.

Generational change is being blamed, with younger consumers not taking up the tea-drinking habits of their parents.

Analyst Richard Caines from market research firm Mintel said tea sales were in long-term decline, dropping by another 5 per cent in 2016.

Reg Whitear and his family enjoy high tea in London's Covent Garden. ( ABC News: Melinda Howells )

"Volume sales of tea are down by about 20 per cent since 2012," Mr Caines said.

"People are drinking tea less frequently than they did years ago.

"And the younger generation are not such big drinkers of tea as older people are."

The market is still worth about $1 billion per year, and 48 per cent of Brits still drink tea at least once per day.

Enjoying a traditional afternoon tea in Covent Garden in London with his wife and son, Reg Whitear said he doesn't stop at one.

"Oh the first thing in the morning is a cup of tea. At least three," he said.

Some of the varieties on offer at a T2 store in London. ( ABC News: Melinda Howells )

At a nearby table, Canadian expatriate Taylor Fornwald said she enjoyed the English ritual of going out for tea.

"Have a little chat, drink some tea, have some cake, it's an enjoyable afternoon," she said.

"I know when I move back home I'll miss going out for tea."

But traditional black tea is facing competition from coffee, soft drinks, and the rising popularity of herbal and fruit teas.

Australian tea company T2 is expanding into international markets, with 16 stores across the UK.

T2 store manager Sherin Talaat says tea drinkers are turning to more exotic varieties. ( ABC News: Melinda Howells )

Store manager Sherin Talaat said social media was influencing the popularity of more exotic types of tea.

"At the moment in this store we have over 130 variations," she said.

"Things like matcha and turmeric are extremely popular: they're key ingredients customers are looking for."