More than 300,000 consumers a year are having payment protection insurance mis-selling claims rejected by banks. Most will be  legitimate claims, but the banks feel it is worth rejecting as many as possible out of hand because only 16% will pursue  their complaint to the Ombudsman.

Given that nine in ten complaints that go to the Ombudsman are upheld and the average payout is £3,000, the banks' refusal to  obey the rules could be saving them about £700m a year.

The Financial Services Authority should keep this figure in mind when investigating how these complaints are handled and  deciding what sanctions to impose.

The banks' behaviour over PPI has been reprehensible from the start. The wanton mis-selling was based on an imperative to  soak the customer at any cost. Hence insurance was flogged to the unemployed, the self-employed, students and even those who  were mentally incapable of making sound financial decisions.

Now the banks have a new tactic to fob off complainants. They will send a letter, typically within a month, indicating that  your type of complaint is unlikely to be successful.

The chances are they have not even bothered to look at it, but they know that 84% of people won't bother to pursue the issue.

Don't be fooled. Write and complain again - and then go to the Ombudsman, who will look at your dispute without taking sides.

It is now ten months since the FSA tore into the banks for not handling PPI complaints properly. The Ombudsman has told the  banks how it expects complaints to be handled.

Yet in their arrogance, the banks are choosing to ignore both, resulting in 1,000 complaints a week still reaching the  Ombudsman. If the banks were playing by the rules, just a fraction of these would be upheld - instead consumers are winning  in more than 90% of cases.

The FSA must act decisively and without delay to end this farce once and for all. Hefty, punishing fines are the only way to  make banks listen.

And if directors or senior managers can be proved to have colluded in the mishandling of complaints, they, too, should face  the toughest punishment.