You can apply to extend your Tier 1 Investor visa whether you are currently inside or outside the UK. Please note, however, that separate applications will be needed for any dependants accompanying you. Whether you are inside or outside the UK, you must apply online to extend your visa.
Ask our Tier 1 Investor visa extension lawyers for advice and guidance in relation to the preparation of your application, so that you can be sure of complying with Home Office requirements.