A Chinese businessman in Britain has told Sky News he sells up to £5,000 worth of baby milk to China every week, which he buys off the shelves of UK supermarkets.
High demand in China for foreign baby formula has led retailers here to ration the amount customers can buy in an attempt to stop it being bought in bulk and sold abroad.
The entrepreneur based in Cumbria, who didn't want to be identified, said he could make more than a 100% mark up on each tin.
"I buy milk from supermarkets and then I sell it through a popular Chinese online shop called Taobao. It's the equivalent of eBay," He said.
"I buy it for between £7 to £9.50 and I sell it between £16.50 to about 19.50."
The website Taobao has over 5.4 million searches for the word 'Aptamil' baby formula, and UK products listed for sale at inflated prices.
The businessman continued: "There are three types of people like us. The first you get students or visitors who get asked to send one or two tins back to family or friends. Then you get small and medium businesses like me.
"The third group of people are the biggest sellers usually based in London or Portsmouth. They buy directly from health distributors - the kind of people who supply supermarkets. These people buy orders of £20,000."
This flood of exporting has led to rationing in major supermarkets including Sainsbury's, Tesco, Morrisons and Asda.
They will only sell individuals two tins a day of certain products following concerns raised by manufacturers Danone.
Sky News spoke to mothers in Leicester who have already noticed a shortage.
Holly Drury, mother of five-month-old Ellis, said: "In the last three to four weeks I've been in my local store and it's not been in stock. I had to ask the customer services to get one off the delivery van for me."
Ali Chambers, mother of four-month old Ava, added: "If it runs out I'm concerned about what other milk is available. Obviously cow's milk isn't an alternative until she's 12 months, and at this stage I can't go back to breast feeding."
The two-tin restrictions have not stopped the businessman in Cumbria selling to China.
He said: "Before the limit I used to have about a 10 miles radius to shop every day, to every shop available that sells Cow & Gate and Aptamil.
"Since the limit I find myself travelling further in a radius of 25 miles. My petrol costs will go up from about £100 pounds a month to £250 a month."
Foreign baby milk is popular in China because locally-produced products have in the past been contaminated causing widespread illness and some deaths.
Times Journalist in Beijing, Leo Lewis, said: "This growing middle class in China have got more money and they've got more concerns about health issues.
"They've been looking for ways to protect their families and one of the big perceptions is that foreign baby milk formula is simply more reliable, it is held to higher standards and its more stringently regulated in those countries."
Hong Kong milk smugglers have already been detained after they banned exports to china over fears their domestic supplies were being drained.
The stem on Hong Kong supplies meant China turned to Australia which put restrictions on sales earlier this year along with New Zealand.
Now they're looking to the UK and other European countries for supplies.
Parent groups are angry that British mothers have been left with this concern.
Siobhan Freegard, founder of Netmums.com parenting website, said: "It is scaremongering to suggest the shelves of British supermarkets will be stripped bare of formula.
"If demand in China is up as much as is being claimed, it's an opportunity for formula firms to take on extra workers and create jobs in the UK and around the world to meet demand.
"But even talk of shortages will worry British mums. Not being able to feed your baby hits at the most primeval fears of every mother. And if there are shortages of specific brands, this will cause problems as children get used to the taste of a formula and can be fussy if it is switched for another," she added.
Danone, the manufacturers of Aptamil and Cow & Gate, said: "We understand that the increased demand is a result of unofficial exports to China to satisfy the needs of Chinese parents who want international brands for their babies.
"We do not export our products - the powdered baby milk formula we sell is made for UK babies and labelled according to UK regulations."
The firm added: "We would like to apologise to parents for any inconvenience caused by the introduction of this limit.
"We know that most parents only buy one pack at a time and so we hope that the impact of this limit on UK parents will be minimal."