I have my AIB in a few weeks and I was wondering do I need to have cleared security before I start Dartmouth? How long does it take? I have been living abroad off and on for the last 5 years and could this prevent my joining?
You must have security clearance before beginning basic training BUT you can complete the application process whilst this is happening.
As long as you are not and never have been involved in any terrorist activity and are not linked to anyone who is, have never been charged with espionage and have never found yourself in any illegal compromising situation which would be seen as inappropriate with regards to the representation of our Country and it's Armed Forces, then you'll be fine - having been living abroad or not. I know that some countries are viewed as hot spots for manipulation of citizens relating to the above, but as long as your criminal history checks out - again you should be fine.
Mine took 6 weeks and I was shitting it the whole time, even whilst in the knowledge that I had nothing to worry about.
You'll see in the publicly available info that you are normally required to have been resident in the UK for the 5 years prior to applying to join, however there is a process called a "residency waiver" that your AFCO may or may not wish to apply for on your behalf.
Some applicants are required to provide a police report (saying you are clear of convictions, etc) from where they were resident abroad, hopefully you will be told at the early stages if you need to do this, but once again not everyone seems to have to do this.
Where you were resident abroad will obviously be taken into consideration,as will the length of time you were abroad. Anything over 6 months in any stretch seems to be the point where it becomes an issue.
Obviously all that I've written are general guidelines, your AFCO should be the ones to give you the best advice relevant to your own specific application.