With the Bank of England base rate set at 0.5% it is difficult to get high returns form cash at the moment. To retain the purchasing power of your money you need to ensure that the return you are receiving is at least equal to inflation. Otherwise the purchasing power of your money is going down all of the time. Yes you will still have the same amount of money in your bank, but the actual purchasing power of your money will have gone down.
Other options for savers include longer term investments. Longer term investments offer far higher potential returns than investing in cash. However long term investments carry a larger degree of risk and their value can fall.