Your overseas employer needs to decide if they wish to set up a UK branch or a wholly owned subsidiary of their overseas business.
Depending on which they prefer, they and you must provide key documents that can include their assets and accounts and full description of the parent company’s activities and a letter confirming that your employer overseas will establish a branch, or wholly-owned subsidiary in the UK, and the UK business must be the same as the overseas business operation.
What must I provide as evidence?
A valid passport, evidence you can support your UK stay, where you plan to live, proof of English and if applicable TB.
You also need to provide evidence you are employed by the overseas employer, not acting as a sales agent, was recruited outside the UK, hold a senior position in the overseas company, authorised to make business decisions in the UK, employed full-time in the UK and not a majority shareholder which is 50% of the overseas business.