How to treat a German Minijob (marginal part-time job) as UK tax resident

Hi all, I am a German citizen and will move to the UK on a visa and start a full-time job there at a British employer. I will therefore be a UK tax resident and pay tax and NI in the UK for that job. I currently have a marginal part-time job (called mini job from a tax perspective) here in Germany which can be done fully remote and which I plan on keeping when moving to the UK. In Germany those mini jobs (going up to a monthly wage of formerly 450€ now 520€) are tax free (and in most cases free of social security contributions) for the employees. The employer pays a fixed tax rate and social security contribution the the Bundesknappschaft in Germany. The money from such mini job does not count towards my taxable income in Germany (e.g. do not push me into a higher tax band) and is not mentioned in any of my tax reports here in Germany. If I know move to the UK, do I have to report the (in Germany tax free) income to HMRC and if so in what way would it be taxed? Thanks already for your suggestions and answers Regards Sascha

Hi Sascha,
If you are tax resident and domicile then yes. if claiming the remittance basis it depends on whether you remit the incme to the UK. please refer to Paying tax on the remittance basis (Self Assessment helpsheet HS264)
Thank you.