Return to the Mortgage Glossary Home to view explanations for all mortgage terms. What follows is the definition for the term Base Rate as it relates to mortgages in the UK. Base Rate Base rate is the base intrest rate that is set by the Bank of England. Most interest rates (including Mortgage Rates) are linked to the Base Rate. The Bank of England meets monthly to decide what the base rate should be set at. A base rate is sometimes called an index rate. A variable/ flexible Mortgage rate will vary in relation to the Base rate. Previous 10 terms < Bankrupt < Arrears < APR - Annual Percentage Rate < Agreement in Principle < Adverse Credit < Advance < Administration Fee < Additional Security Fee < Added To Loan < Accident, Sickness and Unemployment Insurance (ASU) Next 10 terms Booking Fee and Arrangement Fee  > Building Society  > Buildings Insurance  > Capital and Interest Mortgage  > Capped Rate Mortgages  > Charge  > Charge Certificate  > Completion  > Conditional Insurances  > Contract Race  >