The number of people in the UK with diabetes has broken through the 2m barrier, with experts blaming the growing obesity problem for the rise.
Type 2 diabetes is more associated with adults
The figure, compiled from English GP records and Diabetes UK data for the other nations, is 250,000 higher than previous estimates.
There is no breakdown between the two forms of the disease, but 75% of cases are traditionally type 2.
Health campaigners said the findings should act as a "wake up call".
More than 65% of men and 55% of women in the UK are overweight or obese - the largest cause of type 2 after genetic disposition.
In particular, there has been a surge in the number of children with type 2, practically unheard of a decade ago.
Type 2 diabetes results when either the body does not produce enough of the hormone insulin to break down sugar in the blood, or the body's cells fail to respond to insulin.
Diabetes UK said it expected the rise would have been fuelled by obesity.
Simon O'Neill, the charity's director of care and policy, said: "We knew the situation was worrying but it is even worse than we thought.
"Diabetes is serious and unless everyone with the condition is getting the care and education they need it can lead to heart disease, strokes, kidney disease, amputations and blindness.
"These increasing numbers are putting a massive strain on the NHS and unless it can respond, people's health could spiral downwards,"
And Dr Ian Campbell, president of the National Obesity Forum, agreed.
He said: "The figures are disappointing, but we have been expecting them.
"The true figure will be even higher as many people are not even diagnosed yet.
"It is a result of our overindulgent lifestyle. This should act as a wake up call to the NHS and public."
GP performance data published by the Department of Health revealed 1,766,391 people in England had the condition, while Diabetes UK figures have indicated there are 148,000 cases in Scotland, 92,000 in Wales and 47,000 in Northern Ireland.
A Department of Health spokeswoman said: "We recognise that the number of people developing type 2 diabetes is increasing which is partly due to increasing levels of obesity in the population."
And she added the government was taking measures to improve diabetes services through the national service framework.