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DEFONEOS · Sovereign AI Operating System

DEFONEOS UK SC Clearance — Personal Application Guide (Eligibility, 5 Docs, 3 Referees, 5-Step Procedure)

SC clearance guide SOV33-anchored v1.0 · 13 Jul 2026
CSOAI Ltd · UK Co. 16939677
SIGIL: DEFONEOS-defoneos-sc-clearance-2026-07-13-406417f0c504d97a
Publisher: DEFONEOS Sovereign Substrate · Vercel prod

1. Why this page exists

DEFONEOS — the UK sovereign Defence AI operating system — is procured by UK government buyers who handle SECRET-classified material. Every engagement on the sovereign AI estate requires at least Baseline Personnel Security Standard (BPSS) cleared personnel; SECRET-tier work requires Security Check (SC) clearance. This page is the personal application guide for a contractor or civil servant applying for SC clearance in the context of a DEFONEOS pilot, deployment, or audit.

The guide is written for the named individual, not the procurement sponsor. The sponsor's perspective is in defoneos-mod-dstl.html; the prime's perspective is in defoneos-mod-prime-prime-pitch.html; the auditor's perspective is in defoneos-mod-auditor-counter.html. All three link to this page as the personal-claim surface.

1.1 — Scope

2. Eligibility — who can apply and when

SC clearance is administered by United Kingdom Security Vetting (UKSV), a unit of the Cabinet Office. The applicant must meet four baseline conditions before the application is accepted:

ConditionSourceNote
UK national (or 5+ years residency)UKSVDual nationals reviewed case-by-case
Need-to-know for SECRET-tier workSponsor letterDEFONEOS sponsor letter template in defoneos-mod-dstl.html
No unspent criminal conviction (with limited exceptions)Rehabilitation of Offenders Act 1974 (exemptions)Declared, not hidden — transparency helps
Not subject to a financial vulnerability that could be exploitedUKSVIVA, CCJ, bankruptcy declarations required

Note: SC clearance is for the named individual. The DEFONEOS estate is SC-cleared as a deployment target — it is the individual who is vetted, not the system. The system's classification level determines the pool of cleared individuals who can work on it.

3. The five required documents

Document 1 — Passport (or birth certificate + photo ID)

The primary identity document. If non-UK national, the indefinite-leave-to-remain or settled-status document is also required. The document must be valid for at least 6 months from the application date.

Document 2 — Proof of address (last 5 years)

Utility bills, bank statements, council-tax letters. The 5-year trace must be complete — gaps require an explanatory letter. Most common failure mode: a gap between rental properties, or a recent move to a new address.

Document 3 — Financial history declaration

List of all bank accounts, credit cards, loans, and County Court Judgments for the last 6 years. HMRC SA302 forms for self-employed applicants. The financial history is one of three pillars UKSV assesses; the others are criminal and personal.

Document 4 — Employment history (last 10 years)

Names and addresses of every employer, dates of employment, reasons for leaving. Gaps of more than 30 days require an explanation. DEFONEOS-affiliated engagements count as employment; pilot-staff roles at sovereign primes count as employment; freelance consulting on the sovereign AI estate counts as self-employment.

Document 5 — Sponsor letter (DEFONEOS-specific)

The DEFONEOS pilot or deployment sponsor must issue a letter stating: (a) the role the applicant will perform, (b) the SECRET-tier material the applicant will need to access, (c) the duration of the engagement, (d) the contract reference. The template is in defoneos-mod-dstl.html; the issuance flow is in defoneos-mod-prime-prime-pitch.html.

4. The three referee categories

UKSV requires three referees who have known the applicant for at least 3 years, who are not relatives, and who are themselves of "good standing in the community" (i.e., a professional peer or community leader, not a friend from the pub).

CategoryAcceptableNot acceptable
Professional refereeCurrent or former employer, line manager, project sponsorSubordinate, junior colleague, client contact
Personal referee (UK-based)Long-standing friend of 3+ years, professional peer, community leaderRelative, partner, online-only contact
Character refereeSolicitor, accountant, school teacher, university lecturer, justice-of-the-peaceAnyone with a conflict of interest, any family member

All three referees will be contacted by UKSV; the contact is typically by phone or post. Referees who cannot be reached after 3 attempts will cause the application to be paused. Pre-warn your referees: tell them they will be contacted, by whom, and approximately when.

5. The five-step procedure

  1. Step 1 — Application initiation (T+0): The DEFONEOS sponsor issues the sponsor letter; the applicant completes the UKSV online application form (the BPSS+SC combined pack). Submission triggers the document-check phase. Typical duration: 1-2 weeks.
  2. Step 2 — Document verification (T+2 weeks): UKSV verifies the five documents against external sources (HMRC, Home Office, employer references). Any discrepancy triggers a clarification request; the clock pauses until answered. Typical duration: 2-4 weeks.
  3. Step 3 — Referee interview (T+6 weeks): UKSV contacts the three referees. Each referee interview takes 30-45 minutes and covers the applicant's integrity, reliability, and personal circumstances. Typical duration: 2-4 weeks, depending on referee availability.
  4. Step 4 — Security interview (T+10 weeks): The applicant attends an in-person security interview at a UKSV office (London, Manchester, Belfast, Glasgow, Cardiff, or the regional MOD offices). The interview covers the financial declaration, personal history, and any discrepancy that emerged. Typical duration: 1-2 hours, scheduled within 4 weeks of the request.
  5. Step 5 — Clearance grant (T+14 weeks typical, 6 months worst-case): The case is reviewed by a UKSV adjudicator; the decision is communicated to the applicant and the sponsor. SC clearance is valid for 5 years for military and 7 years for civilians, with a 5-yearly review. The applicant is now cleared to handle SECRET-tier DEFONEOS material.

End-to-end typical: 14-16 weeks. Worst-case: 26 weeks. The DEFONEOS pilot schedule should allow a 16-week buffer between the sponsor letter and the pilot's SECRET-tier work. The 8-week and 12-week DEFCON 760 procurement windows do not provide this buffer — they assume the applicant is already cleared.

6. The three most common rejection causes

Cause 1 — Incomplete financial history

Undeclared County Court Judgments, undisclosed IVA, undisclosed foreign bank accounts. UKSV checks against the Experian and Equifax databases; any undisclosed material is a red flag. The pre-emption: list every account, every judgment, every insolvency event for the last 6 years, with dates and amounts.

Cause 2 — Unreachable referees

Two of the three referees cannot be reached after 3 attempts. The case pauses; the clock restarts only when contact is made. The pre-emption: pre-warn your referees; confirm their phone numbers and emails; ensure they are available for a 30-45 minute call within the next 12 weeks.

Cause 3 — Material discrepancy in employment history

An undisclosed employer, a mis-stated title, a missing 6-month gap. UKSV checks employment against HMRC and Companies House. The pre-emption: the employment-history form must list every engagement including freelance, consulting, and DEFONEOS-specific work. Gaps of more than 30 days require a written explanation.

7. Three alternatives if SC is not feasible in the timeframe

Alternative 1 — BPSS (Baseline Personnel Security Standard)

Faster, less invasive, valid for OFFICIAL-tier work. Takes 2-4 weeks. Sufficient for OFFICIAL-SENSITIVE DEFONEOS pilots; insufficient for SECRET-tier. The 80% of DEFONEOS work that is OFFICIAL or OFFICIAL-SENSITIVE is BPSS-cleared; the 20% that is SECRET requires SC.

Alternative 2 — Counter-signature from a UK prime

If the applicant is embedded in a UK prime's team (BAE, Thales, Leonardo, Babcock, QinetiQ, Leidos UK), the prime's security officer can counter-sign the application, accelerating the case. The DEFONEOS sponsor letter + the prime's counter-signature together move the case to the "fast-track" queue. Saving: 4-6 weeks.

Alternative 3 — Sponsor-side classified-access arrangement

If the pilot is OFFICIAL or OFFICIAL-SENSITIVE only, the applicant can work under the sponsor's classified-access arrangement without holding SC clearance. The DEFONEOS deployment target is SC-cleared; the applicant accesses OFFICIAL material under the sponsor's authority. Common arrangement for the first 12 weeks of a pilot.

8. Appendix A — SIGIL chain of custody

This page is SIGIL-anchored. The chain of custody is:

  1. The applicant downloads the page from the public DEFONEOS surface (the URL on this page's meta block).
  2. The applicant cross-checks the five documents and three referees against the eligibility check-list.
  3. The applicant submits the application via the UKSV portal; the sponsor letter reference is {sigil}.
  4. UKSV contacts the DEFONEOS sponsor at the SIGIL anchor email to confirm the application; the SIGIL anchor is the chain of evidence that the application was DEFONEOS-sponsored.

The SIGIL anchor is also the chain of evidence for the applicant's audit trail — if the application is paused or refused, the applicant can cite the anchor to UKSV's appeals process.

Appendix B — The 5-question BFT-33 audit

The BFT-33 council reviews every SC clearance application for a DEFONEOS-affiliated engagement. The audit has 5 questions:

  1. Q1 — Is the applicant eligible? A — UK national, no unspent conviction, no financial vulnerability, need-to-know. Documented in the eligibility check.
  2. Q2 — Are the 5 documents complete? A — Passport, address, financial, employment, sponsor letter. Documented in the document pack.
  3. Q3 — Are the 3 referees reachable? A — Professional, personal, character. Each pre-warned. Documented in the referee pack.
  4. Q4 — Has the 5-step procedure been followed? A — Application, document verification, referee interview, security interview, clearance grant. Documented in the procedure log.
  5. Q5 — Are the 3 rejection causes pre-empted? A — Incomplete financial history, unreachable referees, employment discrepancy. Pre-empted via the 5 documents + 3 referees pre-warned. Documented in the pre-emption log.

The BFT-33 audit is the chain of evidence for the SC clearance application. The audit is SIGIL-anchored; the SIGIL pack is the chain of custody.

Appendix C — Glossary