The figure represents an increase of 132,000 people diagnosed with diabetes over the last year. A further 850,000 people are thought to have undiagnosed Type 2 diabetes.
Barbara Young, chief executive of Diabetes UK said, "We are hugely concerned that the number of people diagnosed with diabetes has reached 3m for the first time. There is no reason to think this will mark the end of what has been a rapid rise in the condition.
"Instead, all the projections suggest that the 3m figure will be a grim staging post on the road towards a public health emergency. This unfolding tragedy is already putting huge pressure on the NHS and will have potentially devastating consequences for those people who develop the condition. But this is not inevitable.
"By identifying those at high risk of developing Type 2 diabetes, we can ensure they start getting support to make the kind of lifestyle changes that can help prevent it. And by making sure people who have Type 1 or Type 2 diabetes are already getting the care and support they need, we can help them avoid the devastating complications diabetes can cause.”
Tesco and Diabetes UK have jointly announced the new figures to mark the launch of a major new national partnership that will see Tesco, its customers, colleagues and suppliers aim to raise £10m, the biggest donation ever pledged to the charity, to help create a healthier future for people affected by diabetes or at risk of developing it.
The partnership will also fund the biggest-ever public awareness campaign on Type 2 diabetes risk factors, aiming to reach the estimated seven million people at high risk.
Added Young: "I’m delighted Tesco has made Diabetes UK its National Charity Partner, as this will make a real difference in curbing the rise in the condition. Not only will the partnership fund the biggest-ever public health campaign on risk factors and symptoms of Type 2 diabetes, but, crucially, it will be funding pioneering research into a vaccine for Type 1 diabetes."
Experts have warned that unless more is done to prevent Type 2 diabetes and more help is given to help those with the condition, the increase could see the NHS burdened with unsustainable costs, which has huge implications for public health.
Every year in England and Wales, 24,000 people with diabetes die earlier than expected, a situation that is expected to get even worse without urgent action.