G. David Garson in his book Hierarchical Linear Modeling (2003) p. 64. asserts,
"The fact that the intercept component is significant means that the intraclass correlation coefficient, ICC, is also significant..."
I'm actually interested in the converse -- I have a non-significant intercept component in a null model and want to conclude that the ICC is not statistically significant -- but a referee has questioned that reasoning. Garson gives no justification or citation to support the assertion.