NHS figures show 3,208,014 adults are now diagnosed with the condition, with around 850,000 who don't know it.
The rise is being fuelled by cases of Type 2 diabetes, which is linked to obesity and unhealthy lifestyles.
Last year, there were 163,000 new cases in the UK compared to 2012. In 2008, the rise was 167,000. The latest rise means 6% of UK adults are now diagnosed with diabetes.
In 1996, the number of people diagnosed with both types of diabetes was thought to stand at about 1.4 million.
While the overall rise could be partly down to improvements in recording and diagnosis, experts at Diabetes UK, which analysed the figures, said the rise over the last decade shows no signs of slowing down.
Baroness Young, chief executive of Diabetes UK, said: "The big increase in the number of people with diabetes confirms that we are in the middle of an unfolding public health disaster that demands urgent action.
"It is frightening to think that one in 17 people you walk past in the street has been diagnosed with the condition.
"Firstly, we need more focus on preventing Type 2 diabetes, as this is the only way we can bring the rapid rise in diabetes cases under control.
"We also need to address the obesity crisis, which is what is fuelling the increase in Type 2, by making healthy food cheaper and more accessible and by making it easier for people to build physical activity into their lives."