A leading surgeon has warned a "malicious combination" of obesity, poor hydration, high blood pressure and a lack of exercise is behind a surge in cases of kidney stones.

Bhaskar Somani, a consultant urological surgeon at Southampton General Hospital, said admissions for renal stone treatment in England had risen by 20% over the past seven years to more than 90,000, with prevalence up to 50% higher in obese patients.

He said poor diets and lifestyles were "fuelling" the development of the condition, with consumption of too much animal protein and levels of salt and sugar creating the "perfect environment" for stones to form.

"We know diet and lifestyle can be a major cause of stones and, with a year-on-year rise in the number of hospital admissions for renal stones and growing numbers of overweight or obese adults, the potential for the number of cases to soar even higher is huge," explained Mr Somani.

"In Southampton specifically, our numbers have gone up by 40% over the past three years and have resulted in the need for us to recruit a specialist stone nurse and registrar to see patients, as well as set-up virtual clinics by phone - so urology and stone services face a very testing future."

The condition, which affects around 10% to 20% of the male population and 3% to 5% of women between the ages of 20 and 60 years, develops when crystals of salt accumulate into stone-like lumps.

Although the body tries to pass stones out of the urinary system, they can lodge in the kidney tube and cause severe and persistent abdominal and groin pain which, in many cases, can only be corrected through surgery.

Mr Somani spoke out following his team's study - published in the Journal of Endourology - into the association of metabolic syndrome (MetS), a condition caused by the combination of obesity, diabetes, high cholesterol and high blood pressure, and kidney stone disease.

The research, which reviewed literature on 219,255 patients, showed a direct link between MetS and the development of kidney stones, with prevalence highest in those with three or more traits of the condition.

"MetS is closely linked with obesity and being overweight, which is why sufferers will go on to develop other related problems such as high cholesterol, diabetes and high blood pressure," he said.

"Poor eating habits which involve excessive animal protein, salt and sugar intake - which is a significant issue due to the wide availability and consumption of processed foods - fuel the build-up of chemicals in the urine which exacerbates stone formation."

He added: "The problem we have as urologists is that, alongside poor hydration and a lack of exercise, you have a malicious combination of factors which creates the perfect environment for stones to develop."

Mr Somani, who was recently named the regional NHS Emerging Leader of the Year for his work in developing the renal stone service at Southampton General, said kidney stones were often the "forgotten outcome" of weight gain - despite having a negative impact on patients' quality of life.

"The misery and pain caused by kidney stones is significant but, more importantly, stones often act as an indicator of the many other serious health problems patients could go on to suffer without intervention," he said.

"By raising awareness of this issue, we hope to not only see a reduction in cases of kidney stones, but to reinforce the scale of the obesity crisis we face and help people to cut their intake of processed foods, hydrate themselves better and increase participation in exercise."

Mr Somani said all adults could take the simple first step of aiming to drink between two to three litres of water a day to reduce the risk of developing stones, while those who have previously suffered from stones should maintain a daily intake of three litres or more to avoid recurrence.

He added: "It's a small step, but better hydration is a quick and easy way to start making lifestyle improvements and people will begin to see and feel the benefits early on."