When the Bank of England raises interest rates, mortgage payments rise, savings accounts pay more, and the economy slows. This chain of consequences flows from a single decision about a single rate that most people never directly interact with. Understanding how this transmission mechanism works is one of the most practically useful things you can know about economics.
What the base rate actually is
The Bank Rate (or base rate) set by the Bank of England is the overnight interest rate at which commercial banks can borrow money from the central bank to manage their day-to-day cash needs. In the US, the Federal Reserve sets the federal funds rate — the rate at which banks lend to each other overnight. These overnight rates are the anchor of the entire interest rate system.
Why does an overnight rate matter so much? Because banks constantly need to balance their books at the end of each day. Banks with surplus cash lend it to those with shortfalls, and the rate at which they do so is anchored to the central bank rate. This feeds into the rates banks set for every other product: mortgages, savings accounts, personal loans, and business credit.
How the decision is made
In the UK, the Monetary Policy Committee (MPC) — a nine-member committee that includes the Governor of the Bank of England and external independent experts — meets eight times a year and votes on whether to raise, lower, or hold the Bank Rate. The decision is guided by the Bank's mandate: primarily to keep inflation at 2% per year, while supporting economic growth and employment.
Before each meeting, the Bank publishes its Monetary Policy Report (formerly the Inflation Report), which includes economic forecasts and signals the Committee's thinking. Markets study every word carefully, because expectations about future rate decisions are priced into financial instruments months or years in advance.
How rate changes transmit through the economy
When the Bank of England raises the base rate, the transmission works through several channels simultaneously:
Borrowing costs rise: Mortgage rates increase, immediately affecting the 1.5 million UK households on tracker mortgages and those coming off fixed-rate deals. Business loan rates rise, making investment more expensive. Consumers with credit card debt face higher interest charges.
Savings rates rise: Easy-access savings accounts and Cash ISAs pay more, incentivising saving over spending. This directly reduces consumer spending in the economy.
Asset prices fall: Higher rates make future cash flows worth less when discounted back to the present. Share prices, property values, and bond prices all tend to fall when rates rise unexpectedly.
Exchange rate rises: Higher UK rates attract foreign capital seeking better returns. Demand for pounds increases, strengthening sterling. A stronger pound makes UK exports more expensive and imports cheaper — which itself acts to reduce inflation.
The base rate is the gravity well of the financial system — every other interest rate is pulled toward it. When the Bank of England moves it, every borrower, every saver, and every investor in the country feels the pull.
Forward guidance: the power of signals
Central banks have learned that signalling future rate intentions — called forward guidance — can be as powerful as actually changing rates. If the Bank of England clearly signals that rates will remain high for two more years, long-term mortgage rates will immediately price in that expectation. Markets move on expected future rates, not just current ones.
This is why the Governor's speeches and MPC meeting minutes are dissected word by word. The phrase "for an extended period" versus "for a sustained period" in a central bank statement can move bond markets by significant amounts — not because the words themselves mean different things, but because markets interpret them as signals of different timelines for rate changes.
The long lag problem
The most challenging feature of monetary policy is its slowness. The Bank of England estimates that a rate change takes up to two years to have its full effect on inflation. This means the MPC is essentially setting policy today based on where it thinks the economy will be in two years — with significant uncertainty on both sides. This is why central banks frequently get the timing wrong: they are inevitably acting on imperfect forecasts of a future they cannot precisely predict.