An earlier tweet said:<p><pre><code> I am off to London tomorrow, to teach
Advanced TDD, and Clojure.
-- https://mobile.twitter.com/unclebobmartin/status/140244588609802240
</code></pre>
I'm no expert on this, but when someone says they'll be teaching, the immediate impression given (rightly or wrongly) is that they'll be paid for it. If he doesn't have the right visa, there will be problems.<p>It may be that he was effectively coming to speak at meetings, and my understanding is that doing so should be fine. But if he says something about teaching, it's plausible that the officer will become suspicious, and then it becomes a complete lottery.<p>This is all speculation, and I wait with interest to see his more comprehensive report.