Class 'Model' not found - module development

Hi all,

I would like to use a a Model in a module I’m developing for EE 2.0 and have run into a problem. I’ve got the model in the /third_party/my_module/models/ directory and calling it with;

$this->EE->load->model('my_model');

in my mcp.my_module.php file. It seems to find the model OK and attempts to load it but then fails with a PHP error;

Fatal error: Class 'Model' not found in /home/xxxx/public_html/system/expressionengine/third_party/my_module/models/my_model.php on line 3

My model is:

class My_model extends Model {

    function My_model()
    {
        parent::Model();
    }
}

Does anyone know what’s up here? Bug in EE or my code…?

Thanks in advance.