More than 150 years after Anna, 7th Duchess of Bedford, invented afternoon tea in the garden with some dainty sandwiches, she has been proved scientifically right: the milk goes in first.

Despite the protestations of the milk-second brigade, led currently by the Labour veteran Tony Benn and posthumously by George Orwell, the results of a two-month analysis by a chemical engineer "proves" that tea tastes better if poured over the milk.

In the Duchess's case, she was doing it to protect her fine bone china. But Andrew Stapley, of Loughborough University, said yesterday that pouring tea on the milk prevented the "denaturation of milk proteins". If tea was already in the cup, droplets of milk hitting the hot water were more likely to degrade slightly and taste a little stale, he said.

Dr Stapley said it was essential to use soft water, warm the pot properly and allow the tea - loose leaf Assam is best - to brew for three minutes. When it was drunk, the best temperature was 60C to 65C "to avoid vulgar slurping".

Publication of the findings was designed to coincide with the centenary of the birth of Orwell, who wrote about the scourges of totalitarianism and putting the milk in first.

Giving his verdict yesterday on the "scientifically approved" tea, Mr Benn declared it "very tasty, delicious", but still demurred from the new wisdom. "I take Orwell's view," he insisted. "You put the tea in first, then you know how much milk you need to put in to get exactly the right colour."