Work for overseas company while staying in the UK

Hi, I have a question about UK income or foreign income. if just moved in UK after 6 April. Before I arrived UK and I am not a UK tax resident before I moved in. Before I moved in, I lived and worked full time overseas. After I moved I, I still worked (part time or full time) for the overseas company as an employee and earned salary. I wonder if this salary is UK source or foreign income? Shall I report it in SA100 or SA106? Is there any NI payable as a result of this salary? Thanks

Hi elsie,
This is foreign income.
Please see guidance here:
Tax on foreign income
Thank you.