Most overseas employers are subject to UK national insurance on their UK staff salaries when they have a taxable presence in the UK for PAYE purposes.
If the non-UK employer has all of their UK employees working from home and does not have a physical address/office, subsidiary, branch, or taxable presence, it is likely that they will not be subject to employers' National Insurance on their UK staff wages.
There are special types of PAYE Schemes for this type of arrangement that you need to operate in this instance, such as:
For help with setting your PAYE Scheme, UK Workplace Pension, payroll processing and other UK employment tax advice, please contact us at +44 7395 534661 or visit info@spondoo.co.uk
Note - you do NOT need a UK bank account to use our payroll or workplace pension/auto enrolment services.