Britain's foremost expert on the E.coli bug has warned parents to keep young children away from farms because of high infection risks.

Professor Hugh Pennington, who spearheaded the inquiry into the E.coli outbreak which claimed 21 lives in Scotland three years ago, told BBC1's Countryfile that children under five were most at risk of contracting the deadly bug.

He said: "I think I would go to the extreme of saying that perhaps it is unwise to take a five or under five-year-old on a farm visit because we have had such serious complication in the very small number of kids who've been infected.

"They've had such a hard time of it, it's hardly worth exposing them to the risk."

Brain damage

Professor Pennington's comments follow an out of court settlement made to the family of a six-year-old boy who suffered severe brain damage after contracting E.coli on a farm visit.

Tom Dowling became infected during a trip to Bowman's Open Farm in Hertfordshire in 1997, during a school trip.

He nearly died as a result of the bug and now cannot move his arms or legs and can only communicate through blinking.

Tom was the third child to contract the bug from the farm which, alongside London's Brent Council, was held liable for damages.

His mother Tracy said: "Sometimes I think 'why did it happen to Tom?' when to my mind he was the most beautiful child in the world.

"But when I'm feeling more positive, I just make the best of it.

"Looking after Tom - hard as it is - is very rewarding and to see him smile is fantastic."

But Professor Pennington's comments have been criticised by the National Association of Farms for Schools.

Spokesman John Newton-Jones said: "Three years ago we had a full working party from across the industry looking at this and providing proper precautions are put in place, we're quite happy that under-fives can visit farms.

"Whatever you do in life, there are going to be risks attached.

"The important thing is that when you are going to a farm park, you must follow basic hygiene procedures."

Of the 14 million people who visited farms in Britain last year, only a handful contracted E.coli.

Countryfile, BBC1, 1130 GMT on Sunday.