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List of largest islands

This Freedom of Information request asks for a list of the largest islands.

Request for information - Ref No: FOI221075


Thank you for your email of 5 April 2022, requesting information from Ordnance Survey in accordance with the Freedom of Information Act (FOIA) 2000, as set out in the extract below:

“According to the article titled "Where is the centre of Great Britain?" on the Ordnance Survey website, when Great Britain is mapped at the 1:625,000 scale, 401 associated islands are shown. I wish to have a list of those 401 islands. I also wish to know which Ordnance Survey maps, if any, show those 401 islands.”

Our response

I confirm that Ordnance Survey does not hold the information you have requested.

However, under the duty to provide information and assistance in accordance with section 16 of FOIA, we can provide the following which may assist you further in this matter.

It is our understanding this is the article referred to in your request: Where Is The Centre Of Great Britain? | Blog (

This article dates back to 2014, at that time, we maintained two datasets, one at 1:250,000 and another at 1:625,000, these datasets were made available as data in Strategi (250k) and GB (625K). Both were retired and withdrawn, with the GB dataset being the first to go several years before Strategi which was withdrawn in 2016.

We do not therefore hold a record of the list of 401 islands which were used to define GB for the purposes of the article in 2014 or the GB dataset, which was the one most likely used.

Using the OpenData Product Strategi and OS Open Names we have been able to compile a list of names for the 400 largest islands based on the coastline length (attached csv file) and also an A3 map (attached pdf) showing their locations which you may find useful. Note no updates have been made to Strategi since 2016. Please be aware, the list we have provided in response to your request, may not be representative of the list used for the purposes of the blog in 2014 and we are unable to guarantee the accuracy of the information provided.

The information supplied to you continues to be protected by copyright. You are free to use if for your own purposes, including private study and non-commercial research, and for any other purpose authorised by an exception in current copyright law. Documents (except photographs) can be used in the UK without requiring permission for the purposes of news reporting. Any other reuse, for example commercial publication, would require the permission of the copyright holder. Most documents supplied by Ordnance Survey will have been produced within government and will be Crown copyright.

In addition, please note that this data is available to download for free on the OS DataHub (Free OS OpenData Map Downloads | Free Vector & Raster Map Data | OS Data Hub) as Opendata, in the form of Strategi Product and the OS OpenNames Product. By using the DataHub and downloading QGIS it possible for you to carry out your own analysis of our data. Therefore, future requests where we consider the information to be reasonably accessible to you as the applicant, are likely to be considered exempt information under section 21 of the FOIA (Information accessible by other means).

Internal review

Your enquiry has been processed according to the Freedom of Information Act (FOIA) 2000. If you are unhappy with our response, you may request an internal review with our Internal Review Officer by contacting them, within two months of receipt of our final response to your Freedom of Information (FOI) request, as follows:

Internal Review Officer
Customer Service Centre
Ordnance Survey
Adanac Drive
SO16 0AS

Contact us via our FoI form

Please include the reference number above. You may request an internal review where you believe Ordnance Survey has:

  • Failed to respond to your request within the time limits (normally 20 working days)
  • Failed to tell you whether or not we hold the information
  • Failed to provide the information you have requested
  • Failed to explain the reasons for refusing a request
  • Failed to correctly apply an exemption or exception

The Internal Review Officer will not have been involved in the original decision. They will conduct an independent internal review and will inform you of the outcome of the review normally within 20 working days, but exceptionally within 40 working days, in line with the Information Commissioner’s guidance.

The Internal Review Officer will either: uphold the original decision, provide an additional explanation of the exemption/s applied or release further information, if it is considered appropriate to do so.

Appeal to Information Commissioner’s Office (ICO)
If, following the outcome of the internal review you remain unhappy with our response, you may raise an appeal, within three months of receiving our response, with the Information Commissioner’s Office.

Further information can be found on the ICO website ( under ‘Report a concern’ or you may wish to call the ICO helpline on 0303 123 1113.