Getting Christmas wrong is guaranteed to offend. Festooning your home in lurid Christmas lights will offend your neighbours. Buying anti-wrinkle cream will offend wives and girlfriends. And an electric nose and ear hair clipper should offend most men. It's obvious really.

And RSA's decision to aggressively market a direct competitor in the commercial insurance arena is equally guaranteed to offend insurance brokers. And sticking the words “No middleman, so the price you pay is lower” adds insult to injury.

RSA has sent this message to 40,000 small businesses and has 40,000 more already in envelopes.

If it sparks some uninsured firms to take out cover, that will be no bad thing. But it has sent the marketing material to many firms already insured through brokers. Many of those brokers may have been putting substantial chunks of business with RSA, particularly commercial business with Enterprise, the RSA commercial division that has proved popular with broker customers.

There's talk of a backlash, of a boycott, of retaliation. There are insurers that don't have direct arms as competitors and brokers could strengthen their relationships with these firms at the expense of the others. And they can fight off the direct competition through their professionalism and their independent advice – even more important in the commercial market than in personal lines.

But will they? We have heard this fighting talk before. RSA is taking a gamble that talk is all it will be. If it is proved right, other insurers will follow rapidly. With millions of small businesses in the UK, it will be irresistible. And when those millions grow in size, so the direct writers will grow in cover. Once lost, the broker's business will be lost forever.