To open a high interest savings account, you'll typically need to provide proof of identity and address. This usually includes a government-issued ID, such as a passport or driver's licence, and a recent utility bill or bank statement with your name and address. Some banks may also require additional documentation, such as your National Insurance number. It's a good idea to check with the specific bank you're interested in, as requirements can vary. For detailed information, visit the official bank's website or speak to a representative.