Employees of the Foreign and Commonwealth Office and the Department for International Development deployed overseas, in common with most ordinary employees, are kept in the UK's social security system and pay Class 1 National Insurance by the UK's extensive network of international agreements. However, where they are sent abroad to countries where there are no agreements then they will no longer be entitled to pay Class 1 National Insurance after 52 weeks. After this period they can, if they meet certain residence conditions, choose to protect their UK basic state pension and entitlement to bereavement benefit cover, by paying Class 3 National Insurance.
There are special rules for certain groups, such as HM Forces that have no choice but to work outside the UK when required. Social security cover is vital as the nature of their work may be hazardous. These rules keep them in the UK Social Security scheme, paying Class 1 National Insurance Contributions towards the full range of social security benefits. Without this, such groups would need potentially expensive private insurance for themselves and their families, or could be left without income replacement when subsequently sick, disabled or unemployed.
The Government have no plans to change the National Insurance treatments of these two groups when deployed overseas.