US suppliers entering UK defence · 2 of 8
Facility Security Clearance, formerly List X
List X is now Facility Security Clearance. FSC lets a contractor hold and process classified material on its own premises, it cannot be applied for on request, and it is not a prerequisite for bidding in most cases. Every one of those three facts routinely surprises US entrants.
What this involves
- Establish whether the opportunities you are targeting genuinely require FSC, because assuming they do is a common and expensive misreading.
- Identify a viable sponsor, since FSC has to be sponsored by a contracting authority: a UK government department or agency, a supplier that already holds FSC, an overseas government with a bilateral security agreement with the UK, or an international organisation such as NATO.
- Prepare the organisation for assessment, including the governance, personnel and physical security evidence, and the foreign ownership position.
- Sequence FSC against your bidding activity, so clearance is pursued through a route that actually exists rather than pursued in the abstract.
The assumption that costs US entrants the most
Trying to get cleared before you have anything to be cleared for. FSC is sponsored, not requested, and a supplier with no contract, no prime relationship and no government sponsor has no route to it. The correct sequence for most US entrants runs the other way: win or subcontract on work that does not require it, build the UK relationship, and let the sponsorship follow the requirement.
Why it matters
Misunderstanding this one point sends US suppliers down a months-long dead end, or stops them bidding at all on the assumption they are ineligible. Getting the sequence right is often the single highest-value piece of advice in a UK entry strategy.
Common questions
What replaced List X?
Facility Security Clearance, or FSC. MOD has moved to the FSC terminology and policy framework. A facility clearance allows a contractor to hold, process or manufacture classified material on its own premises at the relevant level. If you are reading older guidance referring to List X, the underlying concept carries across but check the current FSC policy rather than relying on the legacy material.
Do we need Facility Security Clearance to bid for MOD contracts?
In most cases no. MOD guidance is that facility clearance is not a prerequisite for bidding other than in exceptional circumstances. It becomes relevant where you will hold classified material on your own premises. Many suppliers work productively with MOD without ever needing it, and treating it as an entry gate is one of the more costly misconceptions in this market.
How does a US-owned company get FSC?
It must be sponsored by a contracting authority, which can be a UK government department or agency, a supplier that already holds FSC, an overseas government with which the UK has a bilateral security agreement, or an international organisation such as NATO. You cannot apply on request. Alongside sponsorship, the foreign ownership, control and influence position has to be satisfactory, which for a US-parented entity is usually the substantive piece of work.
Cleared support
Consultants cleared to Baseline Personnel Security Standard and Security Check, with Developed Vetting cleared personnel available where a requirement demands it.
Reviewed 22 August 2026 against MOD published policy. Nothing here is legal, export control or security advice, and defence policy moves: confirm the current published position before planning around anything on this page.
The rest of the entry picture
See the full UK entry overview for US defence suppliers, or our MOD bid writing service.
Testing whether the UK is worth it?
That is the right question and we will answer it straight, including when the answer is not yet. A director replies. We work US business hours by arrangement.
Facility Security Clearance, formerly List X
What do you supply, who buys it in the US today, and what has prompted the UK question?