Oesophageal Squamous Cell Carcinoma (OSCC) is a cancer of the food pipe that affects around 2000 patients in the UK every year. It is often detected at an advanced stage, resulting in poor survival (5-year survival less than 20%). Early detection can improve survival (5-year survival \>70%). Therefore, early detection is vital to improving survival. There are no national screening guidelines, and an endoscopy (A camera test to look at the food pipe) is the only available test to detect OSCC. Early detection of OSCC is challenging for many reasons. Firstly, early disease symptoms are non-specific, which patients often overlook. Secondly, 'Alarm' symptoms such as weight loss, difficulty swallowing or vomiting blood are signs of advanced stage. Lastly, endoscopy is an invasive test with associated risks and significant discomfort. The investigators propose to develop a breath test for patients with non-specific symptoms. Breath testing has the ideal characteristics for a triage test because it is non-invasive, simple to perform, cost-effective and highly acceptable to patients. The test is based on identifying volatile organic compounds (VOCs, small molecules) that are produced by the cancer and released in breath. The breath test will be offered by General Practitioners (GPs) to patients with non-specific symptoms. Those who test positive will be referred for an urgent camera test, and those who test negative can be reassured.