The retail giant has 2,500 stores, and has said the claims of other stores to back British farming using flags and posters were often little more than window dressing.
The company claimed it will be the first major retailer to switch all fresh meat - including the meat used in ready meals and sandwiches - to 100 per cent British.
It has called on more supermarkets, fast food chains and restaurants to back homegrown goods.
The move makes economic sense at a time when the pound has fallen in value against other currencies, which has made imports more expensive.
Research by the Co-op shows that the value of meat coming into the country from the EU and elsewhere has risen from £3b to £6.2b.
More than £5b worth of meat is now shipped in from other EU states. Countries in Asia and Australasia account for £804 million worth of imports, followed by Latin America at £345m.
Ireland is the biggest beneficiary of EU meat trade with the UK, with £1.45b of meat arriving in the UK from across the Irish Sea.
The Co-op already only sells British beef, chicken, ham, pork, sausages, duck and turkey and only uses British meat in all its own-label chilled ready meals, pies and sandwiches.
It will go further from today and sell only 100 per cent British bacon and lamb - dropping Danish bacon and New Zealand lamb.
Almost a tenth of all meat imports come from Denmark, which exports £550m of meat into Britain each year, while New Zealand lamb accounts for £291m worth of UK imports.
Chief executive of the National Pig Association, Zoe Davies, called for other supermarkets to follow. She said: "Around half of the pork consumed in the UK is imported."
"Fluctuating currency markets and imports which are cheaper because of lower welfare standards can significantly impact the cost of home-produced pork, making it harder for farmers to make a living."
"We call on more retailers and food providers to ... go 100 per cent British."
Jo Whitfield, chief executive of food at the Co-op, said: "British consumers will be shocked to see how meat imports have grown while at the same time retailers hang out the bunting and claim to back British farmers."
"Only the Co-op offers 100 per cent British fresh meat all year round ... We can do this because we're owned by members, not shareholders, and can invest long-term in what matters to communities."
The move away from imports will not include cured meats such as chorizo.
A survey published last week found 50 per cent of the population will make a conscious effort to spend more money on British businesses and brands during the two-year Brexit negotiating period.
