Programmatically skip an NUnit test

Is there a way for an NUnit test to end and tell the test runner that it should be considered skipped/ignored, rather than succeeded or failed?

My motivation for this is that I have a few tests that don't apply in certain circumstances, but this can't be determined until the test (or maybe the fixture) starts running.

Obviously in these circumstances I could just return from the test and allow it to succeed, but (a) this seems wrong and (b) I'd like to know that tests have been skipped.

I am aware of the [Ignore] attribute, but this is compiled-in. I'm looking for a run-time, programmatic equivalent. Something like:

if (testNotApplicable)
    throw new NUnit.Framework.IgnoreTest("Not applicable");

Or is programmatically skipping a test just wrong? If so, what should I be doing?

Assert.Ignore();

is specifically what you're asking for, though there is also:

Assert.Inconclusive();

I am having a TestInit(), TestInitialize method where there is a condition like:

    //This flag is the most important.False means we want to just ignore that tests
    if (!RunFullTests)
        Assert.Inconclusive();

RunFullTests is a global Boolean variable located in a constant class. If we set this to false the whole test class will be ignored and all the tests under this class will be ignored.

I use this when there are integration tests.