Originally Posted by
RexBanner
I take your point but I’d argue Climb Now is pretty clear and unambiguous, regardless of any difference to ICAO.
I would say that that is a matter of personal interpretation. When you have pilots from all over the world flying into an area such as London I would think that more than a few would have trouble interpreting the word 'Now' as meaning unrestricted. For me personally that's too generic a word and is far too ambiguous for it to be used in such a congested setting as London airspace. But that's just my opinion.