I do believe that the MML electrification was one of the first things to be announced as cancelled by the new "don't blame us, blame Labour" coalition government at the spending review.
I don't think it was that straight forward. The original NR electrification strategy made the GWML and MML both high priorites. Then Labour decided to jump in and announce that the GWML and NW would be done first, and MML would go on the back burner.
The ConDems then said they'd review whether of not the MML was actually the better choice, but then confirmed they'd basically carry on with Labour's plans.
I don't think it is really possible to say that the MML has been 'cancelled' under those circumstances. Various road schemes have definitely been formally cancelled, but you can't cancel a project that has never been announced IMHO.