Sales of porridge and oatmeal have nearly doubled in the last five years, according to market analysts Mintel.
Research suggests porridge can cut obesity in children
The health benefits of eating oats are part of the reason behind the revival of the hot breakfast cereal, it said.
Sales of porridge and oatmeal soared by 81% to £85m from 2000 to 2005. Britons ate 50,000 tonnes of oats last year.
"The success of porridge is almost entirely due to its convenience and its healthy positioning," said Mintel's senior market analyst Julie Sloan.
She said porridge's popularity would continue and it was challenging more adventurous breakfast cereals.
Hot is hot
"The popularity of porridge has seen something of a revolution, cooking up a storm not only in the home but also in Britain's cafes and sandwich shops," said Ms Sloan.
Convenience and health are key requirements for food in the 21st century, she added.
Both single-serve porridge sachets and the traditional oats have been boosted by the recent popularity of hot cereal, says Mintel's Breakfast Cereals in the UK report.
By contrast, the cold cereal market saw sales rise by just 13% over the same five year period.