One of the UK's top knee injury experts has warned amateur footballers to beware the perils of piling on the festive pounds as they get set to return to action in the new year.

Professor David Barrett, a knee and sports injury specialist at Southampton General Hospital, said he expected to see an "avalanche" of new cases in January as overweight and unfit players donned their pads and boots after an overindulgent Christmas.

He said the problems mostly affected men in their mid-30s onwards - mainly those in veteran leagues who "have the mindset of a teenager but the fitness of Father Christmas".

"We see an extra ten to 12% of knee and ankle injuries in the first two or three weeks after the New Year celebrations as middle-aged men take to the pitch without any prior preparation," he explained.

"This period is a real challenge for those who have no residual fitness but dive straight into action at full pace on icy or wet surfaces after solid days of eating unhealthily, festive drinking and staying indoors inactive.

"They really struggle and, as a result, make late tackles, twist or turn awkwardly or tire themselves so much their minds and bodies don't work in tune, often resulting in cartilage, ligament or bone damage."

He also urged caution among those players drafted in as a result of team shortages due to colds and flu throughout the winter.

"We also find this a difficult time for those men who play sporadically - they are often really unfit but get the chance to play due to illness and, when they do, they are simply out of their league."

Prof Barrett, who also leads knee joint surgery and research in orthopaedic engineering at the University of Southampton, said the problems could be avoided with light but regular exercise.

"I think it's fantastic that middle-aged to older men want to keep up their sport and it's important they do, but they won't be able to do that if they inflict a serious but avoidable injury on themselves," he said.

"I would advise them to be sensible about their fitness and ensure they participate in some light training or exercise regularly over Christmas and New Year so they can take to the field at less risk of unnecessary injury."