1 Northern Oesophagogastric Unit, Royal Victoria Infirmary, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK.
2 Northern Oesophagogastric Unit, Royal Victoria Infirmary, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK; School of Medical Education, Newcastle University, Newcastle upon Tyne, UK. Electronic address: awphillips@doctors.net.uk.