Lenders quite often ask for Personal Guarantees on Loans. Residential Mortgages and BTL Mortgages are automatically guaranteed if you borrow in your own name. If you buy a BTL in a SPV, then normally you would be asked to provide a full PG. For Development Finance and Commercial Mortgages, which are ordinarily held in companies, a lender may ask for a PG to cover some of the loan. With Development Finance, it is typical for a lender to ask for 15%-20% of the Build Costs. On a Commercial Mortgage it is common for a Lender to ask for a PG on the amount of the Loan that exceeds 50% of the property value; so a 65% LTV Loan would attract a 15% PG.
