Germany-UK Double Taxation - Help!

Hello! I recently started a job in Germany (November 2023), but will be performing this job remotely from the UK. I am a UK resident, and spend around 70% of my time in the UK, making me (as far as I can see) responsible for paying UK tax on my income. This is my only source of income. I am trying to organize how best to avoid double taxation as per the UK-Germany double taxation agreement. I have tried applying for a certificate of residence in the UK to provide to German authorities, however all I receive back in the post is a letter of confirmation of residence (and on this letter, it specifically states that it is NOT a certificate of residence, and cannot be used to claim relief under double taxation). I have seen other posts which suggest that the best option is just to pay taxes in Germany, and then apply for foreign tax credits when submitting a tax return. I would be happy to do this, although the taxes I would pay are slightly higher. Also, I have seen that in some cases, double-taxation agreements specify that you must organize to pay taxes directly to the correct country, and this can invalidate claims foreign tax credits... Additionally, as I will now need to do a tax return for all of this, when do I need to register by? It seems I've missed the October deadline, but I only started this Job in November so was not aware! I've read through nearly everything I can find on the HMRC website, so any clear advice would be helpful! I'm trying to organize this all preemptively as I can't really afford to take the brunt of paying double tax, even if for a short while... Thank you!

Hi Elliot Howard-Spink,
As you only started in November 2023, the deadline for registering for self assessment is 5 October 2024. as you have not had any income as yet, this is why you have received a letter of confirmation and not a certificate of residence. once you submit your return for 23/24 - after 06/04/24, you can reapply for the certificate of residence.
Further guidance is at Tax on foreign income.
Thank you.

Thank you @HMRC Admin 20. So for the tax that I will pay in Germany between now and April 2024, what do i do about this? Does it count towards foreign tax credits for my UK tax return? Many thanks for your help!

Hi Elliot Howard-Spink,
As you are resident in the UK, but working for a German employer, you will be taxable on the employment income in the UK.  
Your German employer may need to contact the German tax authorities, to arrange for no tax to be deducted from your employment income, as the tax is only payable in the UK.  
You can resubmit a certificate of residence  request, once you are in receipt of the foreign income.
Thank you.

HI HMRC Admin 20, Thank you for your help. To clarify, I can only acquire the certificate following the 6th April 2024, so how can i evidence to my employer (and German authorities) that my tax should be paid in the UK, and therefore not deducted in the meantime? I can't figure out how this matches up with your last response... Many thanks

Reading the current UK-Germany tax treaty in force, it seems that foregin tax credits can contribute towards my UK tax which I will pay in the meantime? "Subject to the provisions of the law of the United Kingdom regarding the allowance as a credit against United Kingdom tax of tax payable in a territory outside the United Kingdom (which shall not affect the general principle hereof): a) German tax payable under the laws of Germany and in accordance with this Convention, whether directly or by deduction, on profits, income or chargeable gains from sources within Germany (excluding in the case of a dividend, tax payable in respect of the profits out of which the dividend is paid) shall be allowed as a credit against any United Kingdom tax computed by reference to the same profits, income or chargeable gains by reference to which the German tax is computed" Is this correct?

Hi,
Any German tax deducted from your employment income (prior to you receiving a UK Certificate of Residence) can be claimed as Foreign Tax Credit Relief in your 2024 tax self assessment tax return:
Tax on foreign income