POSTCODE DISTRICT · ENGLAND

Portsmouth PO1 postcode area

Read the preparedness conclusion for PO1 in Portsmouth, check which council figures apply and find the official warning service for this location.

DISTRICT REPORT SCOPE

Area evidence, not a full-postcode grade

The PO1 prefix covers multiple addresses and may cross council or warning-area boundaries. The 0–6 Data & Preparedness Score below counts documented sources for this district. It is separate from the conditional A–G disruption grade on a full-postcode report.

A–G grade for PO1: not assessed at district level. A complete postcode is needed to check live utility and road incidents and listed emergency-care distance. A grade appears only when all three inputs can be scored. How the full-postcode grade works.

Population density compared with the UK

UK average: 287 residents/km². Figures below cover the named councils.

Portsmouth5,236 residents/km²UK council density percentile: 93/100

ONS mid-2025 population estimates · MYE5

Preparedness conclusion for PO1

A district lookup cannot tell you whether an onward connection is operating.

Portsmouth is 4,949 residents/km² above the UK average of 287 residents/km².

PO1 is associated with the Portsmouth authority. Its resident density can be compared with the UK average, while the availability of a road, rail or ferry connection depends on current conditions. An operator notice can therefore matter even when the address is outside the named warning area.

Check current flooding in England

Local flood evidence for PO1

Recorded flooding

Portsmouth’s strategic assessment identifies Broad Street in Old Portsmouth as a place that has flooded during storm tides. It also lists places elsewhere on Portsea Island. Broad Street is the more useful historical reference for this district, while a past event cannot establish the exposure or access arrangements for an individual building.

Portsmouth strategic flood risk assessment

Official warning area

The Environment Agency publishes an Old Portsmouth warning area distinct from its Southsea and Eastern Portsmouth areas. If an alert names Old Portsmouth, check its mapped boundary before applying it to a place elsewhere in PO1. Use the port or transport operator for current information about an onward connection.

EA Old Portsmouth warning area

Data & Preparedness Score 6/6

All three evidence checks meet the highest level for this report. The score describes the evidence available in this report. It does not measure risk, safety or personal readiness.

Warning coverage 2/2: A named official warning or alert area is documented locally. Check the mapped boundary for your address.
Official guidance 2/2: Local authority or regional preparedness guidance is linked below.
Data completeness 2/2: Council density is available. A local flood record is documented.

How the district score is calculated

Warning coverage earns 2 points for a documented local warning area, 1 for an official service link and 0 when no source can be identified. Guidance earns 2 for a local authority or regional preparedness link, 1 for UK guidance and 0 when neither is available.

Data completeness earns 2 points when council density and a documented local flood record are both available, 1 for either and 0 for neither. The three scores are added. The number or severity of current warnings does not change the score.

Emergency information for PO1

Write down where you will wait or how you will contact your group if a connection is delayed. Confirm with the operator and any relevant official incident information before changing plans.

Portsmouth City Council sets out local flooding contacts and flood management information. Keep the council link and the contact for the building or terminal you use. Follow any route or destination specified in incident instructions rather than assuming the usual waterfront approach is open.

Check a full PO1 postcode

Enter the complete postcode, including its final three characters, to see the nine-indicator evidence breakdown, any supported provisional A–G grade, local incident results and a check against official flood-warning boundaries.

How the nine indicators apply

A district prefix covers many full postcodes. This page has no live A–G disruption grade and does not assess war or nuclear risk. Enter a complete postcode above to see the nine-indicator breakdown for its returned location.

Can contribute to a full-postcode grade: Infrastructure: matched electricity or water incidents where covered. Medical resources: straight-line distance to a listed emergency department. Road access: nearby active TfL events where covered. Missing feeds are excluded, not scored as zero.
Can be shown, without a risk score: Wind direction and speed, one-hour rainfall forecast, and elevation with sampled local relief. These do not establish exposure to a particular incident or protection at a building.
No verified postcode-level assessment: Military targeting, building structure and designated shelter availability. A postcode prefix cannot supply these details.

Full scoring method · Compare full postcodes · UK Emergency Alerts