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Address intelligence by proxy

Exemplar Award Winner- Winner NLPG NSG Exemplar Award ‘Technology Award’ 2010: London Borough of Harrow

Best example of an innovative application of technology using the NLPG/LLPG or the NSG/LSG

In 2009 the London Borough of Harrow’s LLPG Custodian decided to carry out an audit of all its departmental mailing lists with a view to improving address intelligence.

Not surprisingly, the communications department had the most comprehensive list but also had boxes of mail that had been returned to the council via Royal Mail’s ‘Return to Sender’ (RTS) service. The LLPG custodian took the boxes away and started to do an analysis but soon decided that querying the LLPG manually for each returned item was a poor use of time.

The custodian did, however, realise that these items of returned mail were a good source of address intelligence because they came as a result of a postman visiting each address; in other words, a site visit by proxy. The returned items also came back with a label attached by the postman, marked up with the reason for the return. If the process for recording the reason for the returns and comparing them with the LLPG could be streamlined, there would be considerable benefits to the council.

Firstly, the mail returns would provide a valuable source of intelligence to update and improve the LLPG. It would also, in many cases, cut down the need for costly site visits or the need to initiate a further investigation. A return, for example marked as ‘No such address’, might be a perfectly valid address in the LLPG; however, the property itself might, in the interim, have been converted illegally into flats without recourse to planning permission. The return would trigger further investigation and, in due course, result in a gazetteer update.

The solution to the time consuming problem of data entry and record comparison turned out to be simple and inexpensive and makes efficient use of officer time. In the pilot for this project, the mailing list was matched to the LLPG. Using a barcode font already owned by the council, a barcode label was created in tandem with the normal address label and attached to each item sent out by the council.

The custodian created a simple Visual Basic application to handle the returns. This takes an export from the LLPG including the UPRN. The application is connected to an inexpensive barcode scanner which is used to scan the barcode on each item of returned mail. The scanned barcode UPRN is then used as the look-up for the property address. The reason for the return is populated using hotkeys relating to the various return types, streamlining data entry. The process takes a few seconds for each item of returned mail. Once the returns have been entered, a query list for further investigation can be exported.


In the initial pilot there were 14,383 addresses in the mailing of the council’s ‘Vitality’ magazine. From this mailing, there were only 38 returns, just 0.26% of the total, a significant indication of the quality of the gazetteer. Further investigation revealed that 24 of these were occupier related so did not reflect on the LLPG. Seven were marked ‘No such address’ where demolition was underway and these were used to update the LLPG. The remaining seven were marked as ‘Inaccessible’ or ‘Incomplete address’. The returns were checked and not found to be at fault. Investigation of these therefore generated a confidence statistic of the LLPG at 99.1%.

This barcode solution was accomplished at very low cost. An integration project would have been far more costly and this solution will work very well for many of the systems and service areas within the council that generate the largest mailings. The project has shown that the LLPG can become the council’s de facto mailing list, and provide a very good reason for continuing to pay for the ‘return to sender service’.

The use of mailings to verify addresses has meant a significant reduction in the amount of site visits formerly required to check address queries, and has even raised the possibility of using the Royal Mail to answer specific queries in the future.

Key benefits

  • Simple cost effective way of dealing with direct mail returns
  • Improved address change intelligence
  • Provides a snap shot of LLPG quality and accuracy
  • Reduction in officer site visits
  • Process picks up the conversion of single properties into flats both legal and illegal with resulting improvements in Council Tax returns
  • Confidence for other council applications in the completeness and currency of the LLPG
  • 14 different service areas that use the LLPG in their systems will benefit from the improved quality of the gazetteer
  • Citizens benefit because the UPRN underpins Your Nearest searches on the MyHarrow online portal www.harrow.gov.uk/myharrow

View from the authority

“This project has been successful in converting what was previously an untapped resource into tangible address intelligence. The solution has been achieved at a very low cost yet delivered a number of significant benefits. By using Royal Mail’s ‘Return To Sender’ service for the Council’s large scale mailings, we are able to improve our LLPG and Council Tax matching whilst reducing the number of site visits we have to make. All departments that now rely on the LLPG as their single source for addressing will benefit accordingly, as will citizens accessing the ‘My Harrow’ web portal.”

Luke Studden, LLPG Custodian, London Borough of Harrow

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