Savers need to be careful that they pick the top fixed-rate deal on offer, as providers frequently change the rates they are prepared to pay for money over a fixed term.

Banks and building societies can offer a top paying bond for several weeks before withdrawing it from sale. Often its replacement can look lacklustre in comparison while others launch top payers.

On 19 December, Investec Bank launched a one-year fixed-rate bond paying 3.55 per cent before tax (2.84 per cent after tax) and a two-year bond at 4 per cent (3.2 per cent) on a minimum investment of £25,000.

The new bonds are among the top payers over their term. Yorkshire and Clydesdale banks, along with AA Savings, where Halifax/Bank of Scotland is the deposit taker, pay a slightly higher 3.6 per cent (2.88 per cent) fixed for one year.

Yorkshire and Clydesdale banks both pay 4 per cent (3.2 per cent) fixed for two years while at Halifax the rate is 3.85 per cent (3.08 per cent).

Meanwhile, Northern Rock has cut the rates it pays on its fixed-rate tax-free cash Isas, which it offers over the internet. The one-year rate on offer to new savers is now 3 per cent tax-free, down from its previous 3.55 per cent while the two-year rate for savers looking to take out an account now is 3.2 per cent, down from its previous 3.75 per cent.

The top one-year fixed-rate cash Isa comes from Leeds Building Society at 3.25 per cent followed by Aldermore at 3.2 per cent. For two years, the Post Office, where the deposit taker is Bank of Ireland, pays 3.6 per cent while Halifax, C&G and Aldermore pay 3.5 per cent.