About 20 seconds into this clip from the Liberal Democrats' Spring conference at the weekend, you'll see a fine example of how
not to do an introduction.
Clap on the name
As far as the structure of the sequence is concerned, it's a reasonable example of how to use the 'clap on the name' technique to elicit applause (for more on which, see my books):
(1) Identify or hint at the identity of who's being introduced
(2) Say a few words about him/her
(3) Name him/her [Audience applauds]
Be positive and confident about who it is
But it really isn't a very good idea to spend stages (1) and (2) raising questions or doubts about the person you're introducing, or to sound less than 100% sure who it is.
Normally, the 'clap on the name' technique works so that the audience is able to come in before you get to the end of saying the person's name - which has the added advantage of making it sound as though they're all so pleased to see him/her that they can't wait until you've finished to start clapping.
But, in this case there's a delay of a whole second before the applause gets under way - which was almost certainly prompted by the hesitancy shown in leading up to the announcement of his name (and/or possibly even because the audience was still mulling over the controversial implications of the first sentence):
CHAIR: "I'd like to introduce you conference to probably one of the very few MPs in British politics at the moment who is genuinely trusted by the British public (What? - 1: Is he only 'probably' one of them, 2: Are there only 'very few' of them, and 3: Where does that leave all the other LibDem MPs?).
"Its - the - shadow - Treasury - uh - shadow Chancellor of the Exchequer rather (What?Doesn't she know who their most famous MP is or what his job title is?), Vince Cable."
Clips showing Michael Parkinson and Barack Obama using the same technique rather more effectively than this can be seen HERE. 
