To avoid being locked in to the wrong fixed-rate mortgage at a time when the future of interest rates is uncertain - a tracker is a good alternative to the lender's variable rate. Most tracker rates are lower (HSBC 2.39%) than the standard rate (HSBC 3.94%).
HSBC also do not charge an application fee and the rate is just 1.89% above the Bank of England base rate for as long as you keep the mortgage. There are no early redemption penalties if you decide to switch to a fixed rate when the right deal comes along.