Help! I know I'm overlooking something stupid, but can't see it.

I want to float a simle, smallish gif on the left hand side of the text in a very simple xhtml page.

This is the whole paragraph.

<p>Emergency waterleak repairs in southeast London is one of the key services I deliver, seven days a week if need be. A lot of people think this is something that
will only happen in winter during long periods of severe frost. I can assure you that is not at all the case, and have included a list of some of the most frequently
found reasons for a problem of this kind to pop up. Some of these are utterly obvious, or at least will be when you think about it; others are not. And when it
happens and you can not control it, this simple, clean water that we all take for granted can cause an enormous amount of grief. <img {float:right} src="GSR GIF 100.gif" width="100" height="100" alt="water leak repairs Gas Safe Registger logo"/> </p>

The purpose of this exercise, is to leaf all css alone and manipulate am image inline.
When I remove the {float:right} the image displays fine exactly where I put it.
When I add {float:right} I get a dispaly error pointing at the first curly bracket.

Experimented with id, class and various syntaxis, but nada.

Starting to pull my hair out, which I can not afford as there isn't that much left.

Many thanks for any solutions that will allow me to float an image inline.