http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

You are encouraged to use and re-use the Information that is available under 
this licence freely and flexibly, with only a few conditions.

Using Information under this licence
Use of copyright and database right material expressly made available under this
licence (the 'Information') indicates your acceptance of the terms and 
conditions below.

The Licensor grants you a worldwide, royalty-free, perpetual, non-exclusive
licence to use the Information subject to the conditions below.

This licence does not affect your freedom under fair dealing or fair use or any
other copyright or database right exceptions and limitations.

You are free to:
    copy, publish, distribute and transmit the Information;
    adapt the Information;
    exploit the Information commercially and non-commercially for example, by 
        combining it with other Information, or by including it in your own
        product or application.

You must (where you do any of the above):

    acknowledge the source of the Information in your product or application by
    including or linking to any attribution statement specified by the 
    Information Provider(s) and, where possible, provide a link to this licence;

 If the Information Provider does not provide a specific attribution statement,
 you must use the following:

 Contains public sector information licensed under the Open Government Licence 
 v3.0.

If you are using Information from several Information Providers and listing
multiple attributions is not practical in your product or application, you may
include a URI or hyperlink to a resource that contains the required attribution
statements.

These are important conditions of this licence and if you fail to comply with
them the rights granted to you under this licence, or any similar licence
granted by the Licensor, will end automatically.

Exemptions
==========
This licence does not cover:

    personal data in the Information;
    Information that has not been accessed by way of publication or disclosure 
        under information access legislation (including the Freedom of 
        Information Acts for the UK and Scotland) by or with the consent of the
        Information Provider;
    departmental or public sector organisation logos, crests and the Royal Arms
        except where they form an integral part of a document or dataset;
    military insignia;
    third party rights the Information Provider is not authorised to license;
    other intellectual property rights, including patents, trade marks, and
        design rights; and
    identity documents such as the British Passport

Non-endorsement
===============
This licence does not grant you any right to use the Information in a way that
suggests any official status or that the Information Provider and/or Licensor
endorse you or your use of the Information.

No warranty
===========
The Information is licensed 'as is' and the Information Provider and/or Licensor
excludes all representations, warranties, obligations and liabilities in
relation to the Information to the maximum extent permitted by law.

The Information Provider and/or Licensor are not liable for any errors or
omissions in the Information and shall not be liable for any loss, injury or
damage of any kind caused by its use. The Information Provider does not
guarantee the continued supply of the Information.

Governing Law
=============
This licence is governed by the laws of the jurisdiction in which the 
Information Provider has its principal place of business, unless otherwise
specified by the Information Provider.

Definitions
===========
In this licence, the terms below have the following meanings:

'Information' means information protected by copyright or by database right (for
example, literary and artistic works, content, data and source code) offered for
use under the terms of this licence.

'Information Provider' means the person or organisation providing the 
Information under this licence.

'Licensor' means any Information Provider which has the authority to offer
Information under the terms of this licence or the Controller of Her Majesty's
Stationery Office, who has the authority to offer Information subject to Crown
copyright and Crown database rights and Information subject to copyright and
database right that has been assigned to or acquired by the Crown, under the
terms of this licence.

'Use' means doing any act which is restricted by copyright or database right,
whether in the original medium or in any other medium, and includes without
limitation distributing, copying, adapting, modifying as may be technically
necessary to use it in a different mode or format.

'You', 'you' and 'your' means the natural or legal person, or body of persons
corporate or incorporate, acquiring rights in the Information (whether the
Information is obtained directly from the Licensor or otherwise) under this
licence.

About the Open Government Licence
=================================
The Controller of Her Majesty's Stationery Office (HMSO) has developed this
licence as a tool to enable Information Providers in the public sector to
license the use and re-use of their Information under a common open licence. The
Controller invites public sector bodies owning their own copyright and database
rights to permit the use of their Information under this licence.

The Controller of HMSO has authority to license Information subject to copyright
and database right owned by the Crown. The extent of the Controller's offer to
license this Information under the terms of this licence is set out in the UK
Government Licensing Framework.

This is version 3.0 of the Open Government Licence. The Controller of HMSO may,
from time to time, issue new versions of the Open Government Licence. If you are
already using Information under a previous version of the Open Government 
Licence, the terms of that licence will continue to apply.

These terms are compatible with the Creative Commons Attribution License 4.0 and
the Open Data Commons Attribution License, both of which license copyright and
database rights. This means that when the Information is adapted and licensed
under either of those licences, you automatically satisfy the conditions of the
OGL when you comply with the other licence. The OGLv3.0 is Open Definition
compliant.

Further context, best practice and guidance can be found in the UK Government
Licensing Framework section on The National Archives website.
