During the fixed rate period, the interest rate of the product that you have chosen will remain the same, regardless of changes to the Bank Of England Base Rate (BOEBR) or the individual lenders Standard Variable Rate (SVR).
This product tends to be suitable for a client who is cautious and likes to know their exact monthly outgoings and have no immediate changing life plans. Similarly, if you think interest rates will rise in the near future, a fixed rate deal would protect you against that. However, while you are protected if rates go up, you could also end up paying over the odds if interest rates fall during the fixed rate period. This is the risk of buying into a safer product.