Prospective study of accuracy of colonic polyp characterisation in vivo using high resolution white light endoscopy, narrow band imaging and chromoendoscopy.

Inclusion Criteria:

1. Patients over 18 years of age, assessed as fit for routine colonoscopy

2. Patients attending for screening or surveillance colonoscopy meeting the following criteria:

   • Polyp surveillance with at least 3 adenomas or 1 adenoma>10mm at previous colonoscopy
   • Surveillance post colorectal cancer resection
   • Screening with positive faecal occult blood test

Exclusion Criteria:

1. Patients with known colitis or polyposis syndromes
2. Unable or unwilling to give informed consent

The study group therefore would comprise those presenting for 3 yearly follow up or sooner i.e. those with a resected colorectal cancer or those with ≥ three adenomas or one advanced ≥10mm adenoma or those with a positive faecal occult blood test