This study is a single-centre, interventional randomised controlled trial.

Participants will be individually randomised to receive either COMPASS online CBT + "usual care" (standard LTC charity support), or usual care only. Randomisation will be stratified by recruiting charity site to ensure a balance of participants with different LTCs across the intervention and control arm. Randomisation will occur using a 1:1 allocation ratio managed by RECAP software.

Participants randomised to COMPASS will receive access to the online program. It consists of 11 online modules which target challenges associated with living with LTC(s) and includes, amongst other things, psycho-education, patient examples, interactive tasks and goal setting. Participants are linked to a therapist; 'guide', who will provide 6 x 30 minute support sessions delivered fortnightly in the format preferred by the client (phone and/or in-site message).

Participants allocated to the usual care control arm will receive the usual care that is available to them via their charity. All charities include a helpline which can be accessed via telephone or email. The helplines at all charities offer one-off emotional and/or informational support provided by people trained in active listening and/or counselling skills. Additional support avenues that can be accessed may include online support groups, local community support groups and informational resources.

Inclusion Criteria:

• Aged 18 or over
• Have responded to sign posting advise from the LTC charity or responded to an advert placed on a LTC charity website expressing their interest in taking part in the study.
• Speak English to a sufficiently high standard to allow them to interact with digital CBT programs.
• Live in the UK and can provide contact details of their registered general practitioner
• Have an email address to allow them to register with a digital CBT program and have a basic understanding of the internet.
• Scores ≥3 on the shortened patient health questionnaire (PHQ-4) self-report measure of depression and anxiety in relation to their LTC and/or the COVID-19 pandemic.

Exclusion Criteria:

• Evidence of alcohol and/or drug dependency, cognitive impairment, severe mental health disorders, including bipolar disorder or psychosis
• Acute suicidal risk requiring a level of support that cannot be provided by therapists who are supporting patients remotely in their use of digital health interventions.
• Receiving active psychological treatment. Active psychological treatment is defined as receiving treatment from a psychologist/counselor/therapist or engaging with other online psychological treatment interventions.

The data that support the findings of this study will be available on request from the corresponding author. The data will not be available publicly due to privacy or ethical restrictions.

The data will only be available on request.