Short answer. In the UK, stable iodine (potassium iodide 65 mg tablets) is a pharmacy-only (P) medicine 1. Around nuclear sites, tablets are pre-issued in an area set by the local emergency plan: at Sizewell B, to residents and businesses within 1.35 km 4. The UKHSA dose for adults and children from 12 years is 2 tablets (130 mg), taken once and only when instructed 14.
Who receives iodine tablets in advance in the UK?
Pre-distribution depends on where you live. Under the Radiation (Emergency Preparedness and Public Information) Regulations 2019 (REPPIR), the local authority determines a Detailed Emergency Planning Zone (DEPZ) around a site, based on the operator's recommendation 2. Its size varies from site to site 2.
The tablet pre-issue area is set in the local off-site plan. At Sizewell B, Suffolk County Council states: "Stable iodine tablets have been pre-issued to residents and businesses within 1.35 km (0.8 mile) of Sizewell B power station and should only be taken when instructed during a radiation emergency." 4 That 1.35 km zone sits inside the wider DEPZ, and an Outline Planning Zone extends up to about 30 km 4. Visitors without tablets may be directed to an Emergency Holding Area 4.
If you live near another nuclear site, check your local council's emergency planning page. The UK does not publish a national stockpile figure.
What is the UK dose by age?
The UKHSA protocol gives a single dose by age group 1:
| Age group | Dose |
|---|---|
| Adults and children from 12 years (including pregnant or breastfeeding) | 2 tablets (130 mg potassium iodide = 100 mg iodine) |
| Children 3 to 12 years | 1 tablet (65 mg = 50 mg iodine) |
| Children 1 month to 3 years | 1/2 tablet (32 mg = 25 mg iodine) |
| Neonates (birth to 1 month) | 1/4 tablet (16 mg = 12.5 mg iodine) |
When should it be taken?
Only when instructed during a radiation emergency 4. According to the UKHSA protocol, it is a single dose given shortly before or as soon as possible after exposure, but not once 24 hours have passed, because starting later may do more harm than good 1. One dose protects against exposure lasting up to 24 hours 1.
Iodine protects only the thyroid from radioactive iodine. It does not replace sheltering indoors, which UKHSA says "provides a high degree of protection from breathing in radioactive material in the air" 5. See Potassium iodide (KI): when to take it and who needs it.
Can I buy potassium iodide in the UK?
The UKHSA protocol lists potassium iodide 65 mg tablets in the legal category "Pharmacy only (P) medicine", meaning no prescription is required 1. Whether pharmacies actually stock it for retail sale was not checked. The official advice remains to take it only on instruction 4.
Who regulates nuclear emergency planning?
Under REPPIR 2019, the regulator for licensed nuclear sites is the Office for Nuclear Regulation (ONR); the Health and Safety Executive (HSE) covers other premises 3.
Frequently asked questions
Should I take iodine as a precaution?
No. Tablets should only be taken when instructed during a radiation emergency 4, and not once 24 hours have passed since exposure 1.
Can pregnant women take potassium iodide?
The UKHSA protocol includes pregnant and breastfeeding women in the adult dose of 2 tablets (130 mg) 1.
How far from a power station are tablets issued?
It depends on the local plan. At Sizewell B, the pre-issue area is 1.35 km 4; DEPZ sizes vary by site 2.
Do I need a prescription?
No. Potassium iodide 65 mg is a pharmacy-only (P) medicine 1.
Sources
- UK Health Security Agency (hosted by NHS England) — Protocol for the administration of potassium iodide 65mg tablets to adults and children exposed to or at risk of exposure to radioactive iodine in an emergency situation (v3.00) — https://www.england.nhs.uk/wp-content/uploads/2016/03/PRN01656-Potassium-IODIDE-Protocol-65-v3.00.pdf (accessed 2026-10-20)
- legislation.gov.uk (The National Archives) — The Radiation (Emergency Preparedness and Public Information) Regulations 2019, regulation 8 — https://www.legislation.gov.uk/uksi/2019/703/regulation/8/made (accessed 2026-10-20)
- legislation.gov.uk (The National Archives) — The Radiation (Emergency Preparedness and Public Information) Regulations 2019, regulation 2 (interpretation: 'regulator') — https://www.legislation.gov.uk/uksi/2019/703/regulation/2/made (accessed 2026-10-20)
- Suffolk County Council — Sizewell B — https://www.suffolk.gov.uk/community-and-safety/emergency-planning/sizewell-b (accessed 2026-10-20)
- UK Health Security Agency — Nuclear emergencies: information for the public — https://www.gov.uk/government/publications/nuclear-emergencies-information-for-the-public/nuclear-emergencies-information-for-the-public (accessed 2026-10-20)
Turn this into action
Your plan for United Kingdom, worked out for your household.
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Sources
- UK Health Security Agency (hosted by NHS England) · Protocol for the administration of potassium iodide 65mg tablets to adults and children exposed to or at risk of exposure to radioactive iodine in an emergency situation (v3.00) checked 2026-10-20
- legislation.gov.uk (The National Archives) · The Radiation (Emergency Preparedness and Public Information) Regulations 2019, regulation 8 checked 2026-10-20
- legislation.gov.uk (The National Archives) · The Radiation (Emergency Preparedness and Public Information) Regulations 2019, regulation 2 (interpretation: 'regulator') checked 2026-10-20
- Suffolk County Council · Sizewell B checked 2026-10-20
- UK Health Security Agency · Nuclear emergencies: information for the public checked 2026-10-20