[1] Ninewells Hosp, Gastrointestinal Unit, Dundee DD1 9SY, Scotland
[2] Royal Derby Hosp, Derby Digest Dis Ctr, Derby, England
[3] Univ Coll London Hosp, Dept Surg, London, England
[4] Royal Devon & Exeter Hosp, Dept Gastroenterol, Exeter, Devon, England
[5] Western Gen Hosp, Gastrointestinal Unit, Edinburgh EH4 2XU, Midlothian, Scotland
[6] Crohns & Colitis UK NACC, St Albans, England
[7] St George Hosp, Dept Paediat, London, England
[8] St Marys Hosp, Dept Gastroenterol, London, England
[9] Univ Hosp N Tees, Dept Gastroenterol, Stockton On Tees, England
[10] Royal London Hosp, Endoscopy Unit, London, England
[11] Univ Coll London Hosp, Dept Gastroenterol, London, England