A variation on a theme, where you let the home you are currently living in, so that you can facilitate the purchase of your new home. You need to obtain permission to let from your current lender, and they may not agree depending on their appetite for risk. They may also alter the interest rate you pay. You may need to review the market for other options.
Your let-to-buy is then treated like a traditional buy-to-let application, and your new home purchase would be a related, but isolated, application.
The Financial Conduct Authority does not regulate Let to Buy mortgages