Low cash ISA rates mean losing money - can you beat the system?

It's that time of year when you need to start thinking of how to use your annual ISA (Individual Savings Account) allowance. Failing to do this will mean missing out on the valuable tax avoidance benefits of these accounts.

However, even with tax-free interest, it's hard to keep pace with inflation, as the best cash ISAs on the market offer around 3%, while prices are rising 4% a year according to the government consumer price index, or 5.1% on the retail price index. So what can you do?