I was going to go for 3. OK, I'll go for three and a half because the judge, in the current climate, won't want to be seen to be overly lenient in such a high-profile case. Out in just under 18 months after which he'll have about 4 months under curfew with an electronic tag*.
* - I think, from memory, that's about as long as it can be but if anyone knows different, feel free to correct me.