Inclusion Criteria

• Adults aged ≥ 18 years diagnosed with head and neck cancer (HNC)
• Capacity to provide informed written consent
• Histological diagnosis of squamous cell carcinoma of the oral cavity, oropharynx, nasopharynx, larynx, hypopharynx or unknown squamous cell primary of head and neck origin histologically confirmed
•  (C)RT patients discussed in a Head and Neck MDT meeting and deemed medically fit for an agreed treatment plan for primary or adjuvant radiotherapy ± concurrent or induction chemotherapy (cisplatin or cetuximab)
• Patients planned to receive a minimum of 60Gy to a defined clinical target volume in the oral cavity or oropharynx, or neck levels Ia/b as defined by the current RTOG criteria

Exclusion Criteria

• Known to be pregnant or planning to become pregnant within the trial treatment period
• Photosensitive Epilepsy
• Parotid tumours
• Previous radiotherapy for HNC
• Current/ongoing oral mucositis (OM) and Trismus limiting laser access for treatment
• Patients who are experiencing active heavy tumour bleeding from the mouth (haemorrhage)
• Patients for whom the Multi-Disciplinary Team recommend short course palliative radiotherapy
• Patients on immune suppressant drugs (except low dose steroids)
• Participation in other trials assessing different treatments for OM
• Unable to provide written informed consent