The credit-crunch has been a mixed blessing for borrowers. Millions of people with tracker mortgages have benefited from record low interest rates, but the good times could be over.

The average tracker has increased by 0.24 points to 3.78% since March. While Bank rate is likely to remain on hold for several more months, wholesale markets are already anticipating future increases.

The repayment shock could be huge. Suppose you are on a super-low lifetime tracker at 0.5 points above Bank rate. The best rate now available is 2.89% from First Direct, which would mean repayments shooting up from £753 to £937 on a £200,000 repayment loan.

This could not come at a worse time for borrowers as unemployment is set to rise from 2.2m to 3m by next year.

In the first of a 10-part series, we look at how to recession-proof your mortgage.

1. OVERPAY

As Bank rate has fallen, borrowers with trackers have been advised to keep their repayments at previous levels. Making overpayments in this way reduces your debt faster.

Those who have maintained their payment at the same level as when Bank rate was at 5.75% in December 2007, will have paid off an additional £3,000 of their mortgage so far — assuming a £150,000 repayment loan. If Bank rate stayed at 0.5% for the rest of the term, you would pay off your debt 11 years early assuming you had a 25-year deal, according to L&C Mortgages, a broker.

If you have failed to do this so far, you could make a one-off overpayment or ask your lender to increase payments to previous levels, although there may be a fee of £75 to £100.

Most lenders will charge a fee of 3%-5% for lump-sum overpayments of more than 10% of the outstanding balance per year.

If you subsequently need to draw down some of the money, you should be able to do so as long as you still have the same level of equity as when you took out the loan.

2. CAPITAL REPAYMENTS