Doomsday
Postcode Checker.

Start with an area you recognise, or enter a full postcode above. A district page can help you choose which local questions to ask before looking up a specific address.

• SW1A · Westminster and Wandsworth

  A council record names flooding at Westminster Station and an Environment Agency area names nearby Westminster places. Enter a full postcode to resolve the borough and warning boundary.

• M1 · Manchester

  A council investigation records New Year 2025 flooding near Charles Street, which the River Medlock warning area also names. Check the boundary for your address.

• EH1 · Edinburgh

  An official rail report records flooding at the Mound Tunnel. SEPA’s Edinburgh forecast area is regional, so check current messages for your exact location.

• OX1 · Oxford

  The July 2007 flood record and the Environment Agency’s named Grandpont warning area give you two separate sources for checking a south Oxford address.

• TR7 · Newquay

  The North Cornwall coastal warning area names Newquay and Porth, while street flooding or blocked drainage may need a separate council check.

• CA12 · Keswick

  The Storm Desmond investigation and named River Greta warning areas give useful context, and a full postcode resolves the authority outside town.

• LA23 · Windermere

  Use Westmorland and Furness for the wider council comparison and check your accommodation and onward Lake District journey separately.

• TR26 · St Ives

  St Ives and Newquay share Cornwall’s council density, while the warning map and official instructions vary with the location.

• CT16 · Dover

  Check the named warning area and your transport operator if your plans depend on an onward connection through Dover.

• PO30 · Newport, Isle of Wight

  The Isle of Wight average covers more than Newport, so check island travel and the precise address separately during disruption.

Enter SW1A in the checker and choose Check area. The site opens a district report for Westminster and Wandsworth. Both councils appear because the postcode directory associates SW1A with addresses in both boroughs. The report lists each authority separately and gives the UK comparison alongside it. This is why the first result is a district profile rather than one map point or one density figure.

In the ONS mid-2025 release, Westminster has 9,886 residents per square kilometre and Wandsworth has 9,919. The UK benchmark in the same table is 287. Those numbers tell you that both authorities are densely settled compared with the UK as a whole. They are averages across each borough, so you can use them to compare council areas even though the buildings and streets within SW1A differ.

Now enter SW1A 1AA as a separate full postcode. The postcode directory resolves it to Westminster. The individual report shows a mapped postcode point, Westminster’s density comparison, the settlement classification where available and the result of a live Environment Agency lookup for nearby records. Open the warning itself on the official service before assuming it applies to an address. Results change as warnings are issued, updated or lifted, so this example leaves the live count for you to check.

If you are comparing two addresses in SW1A, begin by resolving both full postcodes. They could fall under different boroughs, and even addresses that share a borough can need different instructions during an incident. Read the named place in any warning and check the source responsible for your building or journey.

Check the location and the scale of the data

Read the postcode, nation and council name at the top. If you entered only the first part of the postcode, check whether more than one authority is listed. If you entered the full code, the marker shows the representative postcode point. Use the street address and official warning map when you need to establish whether a particular building or route is covered. A map marker is useful for orientation when you are unfamiliar with the area.

Next, look at the density comparison. The UK figure is a national benchmark and the local figure is an authority average. They describe where residents live across each area. The settlement-context classification describes the type of area around a postcode, where the source provides it. If two reports have similar density figures, compare their source coverage and local evidence before drawing conclusions about the information you can use.

Read the three parts of the evidence score

The Data & Preparedness Score adds up to two points for each of three checks. Warning coverage tells you whether the report can show a successful live lookup or a documented local warning area, depending on the type of report. Official guidance tells you whether you can follow a local or national source. Data completeness shows whether the relevant location fields or local historical evidence are available. Open the breakdown to see why points were awarded and which information is still missing.

A score can stay the same when a warning is issued because the score measures how much evidence you can access. Use the warning and its instructions to understand the current situation. A lower score can tell you where to go next, such as the official Scottish or Welsh service, a council website or the location fields returned for a full postcode.

Separate current warnings, history and long-term exposure

Read the source name and timestamp before acting on a warning. The Environment Agency feed in the checker covers England. For Scotland, use SEPA. For Wales, use Natural Resources Wales. For Northern Ireland, use nidirect’s flooding information. If a report shows an unavailable feed, follow its official link. When a district report cites historical flooding, read the date and the places named. A recorded event describes past conditions, and an official long-term flood service is the appropriate starting point for questions about exposure over time.

Make the comparison useful for a household

Think about the places your household uses regularly. A home, workplace, school and onward transport connection may each have different instructions. Keep the relevant full addresses and official contacts somewhere you can access offline. When you compare reports, write down the one fact that changes what you would check next. That might be a different council, a different national warning service or a named local area you should look up. Then confirm current instructions with the authority responsible for the affected location.

For a practical next step, choose a way to reach each person if travel or communications are interrupted. Save the official pages you would use and agree who will check the latest instructions. A simple plan can be shared with someone who is away from home or cannot get online.