With less than £249 in savings, 15 million people would run out of money in less than a week if they lost their job. Check out our tips for improving your financial safety net

One in three Britons could not survive a week on their savings

Fifteen million Britons could not survive from one weekend until the next on savings, according to research by HSBC.

The bank has found that 30% of adults have less than £249 set aside as a financial safety net: 11% have some savings but less than £249, while 19% have no savings at all.

Apparently £249 is the equivalent of five days' average take-home pay, though the recommended minimum safety net is three months' pay, which based on the average would be £4,683.

Although the flippant side of me wants to know who the 70% with savings are, the personal finance writer side knows this is very worrying.

The numbers of those claiming jobseeker's allowance announced yesterday show the fastest increase since January, to 1.47 million, and many more are expected to be joining the queue after next week's announcement on public sector spending cuts. And Lloyds has announced that it intends to scrap 4,500 jobs across its group IT operation, leading to the loss of 1,600 permanent UK roles.

Many of those affected will have mortgages to pay. How are they going to cope financially if they have no savings?

As many as four in five of those questioned by HSBC believed they would still be able to pay their mortgage, rent and other bills even if they couldn't work, despite setting aside little or nothing in savings. Just over one third said they would seek government support or apply for jobseeker's allowance, while 22% said they would rely on their partner to cover the bills if they were made redundant.

They are either hopelessly optimistic or just naive.

Even if they qualify for benefits or have income or payment protection insurance, the money will take a while to come through.

And while there is a government support for mortgage interest (SMI) scheme, it pays interest only up to a level equal to the Bank of England's published monthly average mortgage interest rate – currently 3.63%. Given that once you are made redundant you will be unable to remortgage, so once any special deal may have comes to an end, you will revert to your lender's standard variable rate, which could be much higher.

You also have to fit certain criteria - your mortgage has to be less than £200,000, for example – so there is no guarantee that you will get any help at all.

Astonishingly, only one third of those in the HSBC survey said they would apply for jobseeker's allowance, even though only 14% had insurance that would pay out in the event of unemployment or long-term sickness.

If that really is their intention, they had better get saving.

Build up your emergency fund

• Choose an easy-access account, you never know when you might need to use the money. Check for the best rates on the savings table under "Money deals" near the bottom of the Money front.

• Calculate how much you need to save – or how long you need to save for – at the interest rate paid by your chosen account, to achieve your safety net equivalent to three months' salary.

• Set up a monthly standing order into your savings account – that way you won't be tempted to skip a month.

• Work out a realistic weekly budget and stick to it. If you keep using plastic to spend on things you hadn't budgeted for, leave your cards at home and take cash with you to the supermarket.

• Ignore Charlie Bean, deputy governor of the Bank of England, who wants people to go out shopping to save the economy. That's his job, not yours.