Ataxia Telangiectasia (A-T) is an inherited disorder characterised by cerebellar neurodegeneration, immunodeficiency and respiratory disease. People with A-T have abnormal DNA repair and consequently have an increased risk of cancer. Despite this, current guidelines for management of children and young people with A-T do not include cancer surveillance. Improvements in MRI technology have allowed whole-body MRI (WB-MRI) scanning with relatively short acquisition times. Currently, WB-MRI protocols are used for diagnosing and monitoring some primary and secondary cancers, including cancer surveillance in people with the Li-Fraumeni syndrome, which is another genetic cancer predisposition syndrome. Therefore, the research team believe that whole-body MRI provides a safe method for cancer surveillance in children and young people with A-T. However, the investigators do not know whether cancer surveillance in children and young people with A-T using whole-body MRI is feasible and desirable. The research team proposes a feasibility study of MRI-based cancer surveillance with qualitative evaluation of participant experience with the primary aim to establish: * feasibility of whole-body MRI for cancer surveillance in children and young people with A-T * views of, and psychological impact on, participants and families / carers participating in whole-body MRI for cancer surveillance. * feasibility of conducting a formal screening trial in terms of statistical design, sample size, screening interval, comparator arms and international collaboration Completion of this study will provide us with evidence of technical feasibility, very strong evidence of child / family views, a viable formal screening trial design and an engaged international research community, allowing us to proceed to a formal trial establishing the efficacy of a cancer surveillance programme for children and young people with A-T.