Yes, I did spend sometime in Photoshop doing that… quite proud of the bridge…

UPDATE 07/02/2014 :  Read the associated comment on this post from Phil at the Ordnance Survey, quite possibly the best response I’ve ever had on this blog, thank you.

UPDATE 07/02/2014 2: Old Maps at end of this post courtesy of ‘Phil Allen’ FSE Manager at the Ordnance Survey, thank you!

Working with real 3D models of London it sometimes makes sense to place this in context on a boundary map, but I’ve run into to something that’s given me pause for thought….

The City of London is an odd and special part of London I think you’ll agree, I’ve always known it’s administrative boundary as being a little odd (something about bridges…) sure enough on the City of London website there is the boundary showing clearing two bridges are covered in its area.


Now being a GIS sort of fellow I want to download this boundary set, so visiting the OS OpenData site, I see that something’s up whilst one bridge is clearly there on the left, London Bridge has been excluded (hence my clever title).   What does it all mean?   Well I think probably OS Opendata is generalised in some way and this bit got missed… but I don’t really know.   Downloading boundary data from the Greater London Authority data site doesn’t fix things either (it is just the data set the OS gives).

The 3D London Bridge is from Trimble Warehouse (click on image for more 3D London)

So what does this all mean?  Well it means that the OS may well be the ‘authoritative geographic data’ set for the UK, but it doesn’t mean everything you get from it is without ‘issues’.   Know your data, know its limitations, also did I mention OpenStreetMap seems to get it right?  Why am I relying on data from the OS again?

OpenStreetMap better than some give it credit for… (actually maybe not, see comments)

UPDATE 07/02/2014 1:  Read the associated comment on this post from Phil at the Ordnance Survey, quite possibly the best response I’ve ever had on this blog, thank you.

UPDATE 07/02/2014 2: Old Maps below courtesy of ‘Phil Allen’ FSE Manager at the Ordnance Survey, thank you!




  1. Elliot,

    Thank you for your interesting blog around London Bridge, but we are afraid it is not as simple as a mapping generalisation issue. It actually comes with an even more interesting back-story and, should you like us to send them over to you, some historic maps which support the position and show the site of the Old London Bridge.

    That Blackfriars Bridge is within the City for administrative purposes is not in doubt. The southern boundary of the City of London follows the centre of the River Thames except in the case of Blackfriars Bridge which should be shown wholly within the City in accordance with the Blackfriars Bridge Act 1863 – ‘that the said bridge shall be in the parish of St Anne, Blackfriars, City of London’. At this time the City contained some 112 parishes and the legislation clearly transfers the bridge into the City.

    The same situation has not been proven for London Bridge.

    The bridge itself is owned and maintained by the Bridge House Estates, City of London Corporation and some mapping sources show the whole of the bridge included in the City of London boundary. Historically also the boundary of the City is defined by a series of metal bollards and 10 dragons placed at ancient entrances to the City, 2 of which appear at the southern end of London Bridge. That the ‘City’ boundary includes the bridge is not the point in question, it is whether legislative proof exists which places the whole of the bridge in the City of London for administrative purposes.

    Ordnance Survey has to follow very specific rules for defining administrative boundaries and under the Ordnance Survey Act of 1841 has the statutory responsibility for examining, ascertaining and recording boundaries. Markers are informative, but not proof positive, in terms of legislation as hopefully the following will explain.

    Ordnance Survey carried out the original ascertainment of the boundaries in this area between 1841 and 1893. Whether that ascertainment placed the boundary along the bank of the Thames or the centre of flow is unknown, as unfortunately the records of the original perambulation of the area were destroyed by fire after our head office at the time was bombed in WWII. However, the Poor Law Amendment Act 1868 and the Boundary Act 1868 explicitly extended riverside parishes from the high water mark to the centre of flow so at this time the administrative boundary between the City and Southwark to the south was aligned to the centre of the Thames, a situation that has endured to this day as defined by these Acts.

    London Bridge has been the subject of legislation over the years – the London Bridge Act 1967 placed the whole of the bridge within the City ‘for some purposes’ (such as maintenance) but as this states only ‘some’ purposes, Ordnance Survey were not persuaded that this Act altered the administrative boundary between the City and Southwark as defined by the earlier acts.
    Although the City has been granted powers to review its internal ward structure this power does not extend to its external administrative boundary – this power still rests with the Local Government Commission for England.

    The last review of the City’s boundaries indicated that, with the exception of Blackfriars Bridge, the southern boundary is mid stream of the Thames. The view does not seem to have been challenged at the time. See link:—1992/mandatory-reviews/636.-city-of-london-and-its-boundaries-with-city-of-westminster,-camden-lb,-hackney-lb,-islington-lb,-lambeth-lb,-southwark-lb-and-tower-hamlets-lb.pdf

    The relevant chapters from this report are shown below.


    87. The existing boundary follows the centre of the River Thames, except where it diverts round the south of Blackfriars Bridge. We noted that the City Corporation manages the Blackfriars, Southwark and London Bridges, and that the existing arrangements were said not to cause any problems. Neither the City Corporation nor the London Borough of Southwark made proposals for changes to this boundary. We therefore took an interim decision at the time to propose no change to this boundary.

    88. We received one representation in respect of our interim decision, from the Commissioner of Police for the City of London.

    89. The Commissioner expressed the view that, as London Bridge and Southwark Bridge are owned and maintained by the City Corporation, the boundary should be extended to their southern ends, as was the case at Blackfriars Bridge. However, in the absence of any operational justification for the change, we decided not to pursue the suggestion. We have therefore decided to confirm our interim decision to make no proposals as final.

    We hope our rather lengthy response adds some further colour and interest to a famous bridge in London, but at this time the recorded boundary is correctly shown by our Boundary-Line product.

    Of course, Ordnance Survey would, within its statutory responsibility, amend the alignment of the boundary to include London Bridge in the City if further legislative proof came to light.

    Do let us know if you’d like to see the historic maps extracts showing the boundary aligned to the centre of the river.

    Phil Allen, Ordnance Survey Boundaries and FSE Manager
    08456 050505

    • That is an absolutely unexpected but fascinating response to my silly post. Thank you so much for taking the time to respond, I really appreciate it and I will amend my post to point people to your comment!

  2. Great interchange, goes to show no question is too small or stupid to ask LOL have you seen this
    Welcome to Locating London’s Past
    This website allows you to search a wide body of digital resources relating to early modern and eighteenth-century London, and to map the results on to a fully GIS compliant version of John Rocque’s 1746 map.


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