anjaH_alias wrote:

Mrs.Wenceslas wrote:

I think John and Mrs. Hudson were looking for the phone, for it was dangerous for Sherlock to have it - the CIA and others knew that Irene was dead and somebody else could let the picures come out etc-

There is a direct connection to the cigarette Sherlock has taken before - ´Did he take it? Shit!!´. They are definetely looking for cigarettes or drugs. "Caring is not an advantage" says Mycroft before. He knows about what he is talking, has obviously experienced a lot with his little brother.
Taking the phone would mean a deep intervention into Sherlock´s personality rights according to me. Neither Mycroft nor John would do this.

Besides, when Sherlock comes back home after John and Mrs. Hudson's search, he seems to know exactly what has happened and remarks something along the lines of "I hope you haven't messed up my stuff too much" (I know the line wasn't that but it was something along those lines). That hints that they've done a search like this before, and he didn't have the phone before, so how could they have searched for the phone before if he didn't have it before?

I agree with the drugs thing, especially seeing as he did cocaine in the canon and John's reaction to him taking the cigarette.