Well, let's put it this way: we two split, after loong talks we came to an agreement on how to split and then I come with "not sure"/"let's change a bit just"/"let's re-talk"/"I need a bit more time"/"etc".
I suppose You'll say: "listen deaf, I'll give You a bit of time to think about, but do decide if You agree with what we agreed or say just no, and let's get over it".
Additionally, it could include some Commonwealth countries, but this would be the essence of it. Such union, in my opinion would be more viable than any other trade union out there and it would be a great competition economically to the EU or China. If a union like this starts to form after the UK leaves the EU, Brexit would make sense.