Almost a quarter of Britons are consuming plant-based milk alternatives as the popularity of vegan and vegetarian diets continues to grow.

While demand for traditional cow’s milk is falling, sales of alt-milk, made from oats, almonds and coconuts, have surged 10% over the past two years, according to a report.

The report, from Mintel, said 23% of those polled had used plant milk in the three months leading to February this year, up from just 19% in 2018. The shift was particularly marked among women and the under 25s.

Emma Clifford, associate director of UK food and drink at Mintel, said plant-based milk was entering the mainstream as alternative products became more readily available on supermarket shelves. “This is part of a much wider plant-based movement, driven by concerns around health, ethics and the environment.”

Although cow’s milk is still a far bigger market, worth more than £3bn, Britons buy fewer pints than their parents. What was once touted as a one-stop source of health is slipping out of fashion; the average person’s milk consumption in the UK has fallen 50% since the 1950s.

In a significant shift in the UK, the number of vegans – those shunning all animal products including dairy and eggs – has risen. According to the Vegan Society, there were 600,000 vegans in Britain in 2018, up from 150,000 in 2014.

One of the big winners from this shift in consumption is oat milk, with shoppers buying £36m worth last year as sales surged more than 70%. Sales of coconut milk rose 16% and almond milk increased 10% over the same period. The Swedish brand Oatly said its UK sales had increased by nearly 90% to £18m in 2018 and were expected to exceed £30m this year.

Oatly’s UK general manager, Ishen Paran, said consumers were thinking carefully about the environmental impact of their purchases, with alternative milks increasingly appealing also to non vegans. “We’ve seen the introduction of the plastic bag charge, the phasing out of plastic straws and now the growing popularity of oat-based products. Last year we found that younger consumers were choosing to spend more during their grocery shopping on more sustainable options.”

Unchanged from last year, 96% of UK adults still used milk of some kind over the three months to February 2019. Standard cow’s milk remains by far the most widely consumed, at 87%, but its popularity is skewed towards older consumers, peaking at 92% among the over-45s. By comparison, Mintel’s research found, 73% of 16- to 24-year-olds consumed it in 2019, down from 79% last year.

At a time when many dairy farmers are struggling to make a living, Mintel said the 16- to 24-year-old group were the most likely to agree with the statement that dairy farming had a negative impact on the environment. The falling usage among this group was a “potential concern for the industry”, Mintel said.

One of the factors holding back consumption of plant-based milks was consumers being reluctant to cook with them or add them to cups of tea or coffee for fear of ruining the taste. Only 25% of buyers used the products for cooking, compared to 42% of those who bought cow’s milk.

The same was true of hot drinks, where only four in 10 added plant milk, compared with double that figure for traditional milk. The survey of 2,000 consumers claimed, thought, that a fifth of respondents thought “nut milks added more flavour to drinks than cow’s milk”.

Clifford said she thought the dairy industry needed to “rekindle interest in dairy products”.