The UK may have to import milk from Europe within five years if more is not done to help dairy farmers, a leading retailer has warned.
The NFU says the comments should be seen as a wake-up call
Sir Stuart Hampson, chairman of Waitrose owners the John Lewis Partnership, said the sector would become unviable if no action was taken.
Government figures showed that England lost one dairy farm a day in 2005.
Sir Stuart told that Daily Telegraph that it would be "scandalous" if the UK had to import milk.
"There is a lot of scaremongering about tipping points, but we are reaching a point where unless action is taken we won't have a viable sector," said Sir Stuart, who is a former president of the Royal Agricultural Society of England.
Currently the UK only imports around 0.5% of its milk requirements.
Earlier, Sir Stuart welcomed moves by Sainsbury's and Tesco to follow in the footsteps of Waitrose and set up dairy producer groups that invested in the farmers and offered them long-term contracts and financial support.
A Department for Environment, Food and Rural Affairs (DEFRA) spokesman said there was no imminent prospect of the UK becoming a net importer of milk.
"The UK currently exports more fresh liquid milk than it imports - as part of cross-border trade between Northern Ireland and the Republic of Ireland," he said.
"The UK dairy industry produces over 13 billion litres of milk a year with only... seven billion litres going into fresh liquid milk.
"For imports to be a real possibility, production would have to halve or other EU countries would have to produce milk at a much lower price than the UK."
He added: "Neither scenario is very likely."
The chief dairy adviser to the National Farmers Union, Tom Hind, told the BBC that it was significant that the warning had come from the chairman of a major retail chain
"I think it should be seen as a wake-up call for the rest of the entire dairy industry," he said.
The Milk Development Council (MDC) said that while it agreed dairy farmers were under extreme financial pressure, there were signs the industry was beginning to tackle the causes of low profitability on farms.
The head of economics at the MDC, Ken Boyns, said the industry had to make sure milk was produced and processed efficiently, that it developed good relationships in the supply chain, and that it brought out new brands and products that would appeal to customers.