How Many Nukes Does the UK Have?

How many nuclear warheads the United Kingdom holds, what carries them, and its test and treaty record, as of early 2026. Two independent counts (FAS and SIPRI) are shown side by side, every figure cited.

By Marko Visic, BSc Physics

The United Kingdom has an estimated 225 nuclear warheads as of early 2026 (FAS). 120 are deployed on strategic launchers, and 225 are in the military stockpile. SIPRI’s January 2026 count matches.^{[1, 2]}

Warhead count

FAS and SIPRI are compiled by the same analysts and agree on the totals; they split the categories slightly differently. Retired warheads are awaiting dismantlement and are not part of the reserve.

FAS (beginning of 2026 (FAS page updated 2026-06-09))

Deployed (strategic)	120
Reserve / nondeployed	105
Military stockpile	225
Total inventory	225

SIPRI (January 2026 (SIPRI Yearbook 2026, Table 8A.1))

Deployed	120
Stored (nondeployed)	105
Military stockpile	225
Retired, awaiting dismantlement	–
Total inventory	225

Terms: deployed = on missiles or at bomber bases; reserve / stored = non-deployed but in the stockpile; military stockpile = deployed + reserve; retired = withdrawn, awaiting dismantlement; total inventory = stockpile + retired.^{[1, 2]}

How the United Kingdom delivers them

Delivery systems from the latest Nuclear Notebook / SIPRI table (January 2026 (SIPRI Yearbook 2026, Table 8A.4)). A “?” or a dash is the source’s own mark of an uncertain or unstated figure.^[2]

System	Type	Launchers	Per launcher	Warhead × yield	Warheads
Trident II D5	SLBM	48	1–8	1–8 x 100 kt	120
Trident II D5(LE)	SLBM	48	1–8	1–8 × 100 kt	225

four Vanguard-class SSBNs, 16 missile tubes each^[3]
approximately 40 warheads on the SSBN on patrol^[3]
Holbrook warhead, believed very similar to US W76-0^[3]
approximately 100 kt (full yield)^[3]

Blast radius of the United Kingdom’s warheads

For each distinct warhead yield in the United Kingdom’s arsenal, the air-burst 5 psi (most homes destroyed) and 3rd-degree-burn radii, calculated by the same engine as the blast radius calculator.^{[4, 5]}

Yield	5 psi radius	3rd-degree burns	Links
100 kt	1.8 mi (2.9 km)	3 mi (4.8 km)	chart

The United Kingdom’s nuclear tests

Total: 45^[6]
First name date: Hurricane, 1952-10-03^[7]
First site: Monte Bello Islands, off the west coast of Australia^[7]
First yield: about 25^[7]
Nts joint: 24 tests at the Nevada Test Site, 1962-03-01 to 1991-11-26^[8]
Last date site: 1991-11-26, Nevada Test Site^[8]

The name of the last UK test was not captured from a fetched primary source.

Treaty status

NPT: party (nuclear-weapon state); signed 1968-07-01; ratified 1968-11-27; in force 1970-03-05^[9]
CTBT: signed 1996-09-24; ratified 1998-04-06^[10]

Frequently asked questions

How many nuclear weapons does the United Kingdom have?

The United Kingdom has an estimated 225 nuclear warheads as of early 2026, according to the Federation of American Scientists. SIPRI’s January 2026 count is the same.^[1]

When did the United Kingdom first test a nuclear weapon?

The United Kingdom’s first nuclear test is recorded as Hurricane, 1952-10-03.^[7]

Is the United Kingdom part of the Non-Proliferation Treaty?

On the Non-Proliferation Treaty, the United Kingdom is: party (nuclear-weapon state); signed 1968-07-01; ratified 1968-11-27; in force 1970-03-05.^[9]

Every figure on this page comes from a verified primary source, cited inline and listed below. Warhead counts are the Federation of American Scientists’ Status of World Nuclear Forces and SIPRI’s Yearbook; delivery systems come from the Nuclear Notebook; blast radii are calculated from Glasstone & Dolan scaling laws. Candidate and unverified figures are withheld.

Data as of 22 October 2026. By Marko Visic, BSc Physics.

Sources

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