Civil Service 3-Month Footprint Rule

Hi all! Just a quick question...

Do all Civil Service departments for the Social Research Sandwich Placement require a 3-month security clearance? As in, do I have to ensure I am not out the country for 3 or more months?

I have a research internship offer abroad and I would like to do it but I am pushing it until Jan/Feb to give my 100% full answer to the internship until I (hopefully!) get a positive response from Civil Service following the Interview I had this week. What departments do/do not require a 3-month? The information available online is confusing and varies... Hopefully this makes sense!

Thanks!

- Jay