The e-GIF is the foundation of the whole UK e-Government project, and outlines the basic standards used to ensure interoperability of public sector systems. The e-GIF is based around a hierarchy of standards, ensuring that international standards are used where possible, with national standards being subservient to these and government standards being put in place where no others exist. Standards only reach the e-GIF once they are well accepted and have good market support. Where this is not yet the case, they will be flagged as a future direction, as is currently happening with IPv6 and XForms.

The e-GIF is in two parts. Part one contains the high level policy statements, management, implementation and compliance regimes and is reviewed annually. Part two contains the technical policies and tables of the specifications to be used for different purposes and delivery channels. This is reviewed and revised every six months to ensure that it keeps up with the latest developments in what is a fast-moving technical area.

The e-GIF is very XML-based, specifying "adoption of XML as the primary standard for data integration and presentation tools for all public sector systems." It further specifies "XML and XML schemas for data integration", "UML, RDF and XML for data modelling and description language" and "XSL for data transformation". The adoption of these standards provides the syntactic interoperability shown in the earlier diagram.

Semantic interoperability revolves around two sets of standards - those for data and those for metadata.

The data standards are based around a simple architecture for Government data described in the e-Services Development Framework (e-SDF) Primer http://www.govtalk.gov.uk/interoperability/eservices_document2.asp?docnum=497). This provides an overall business-oriented information architecture for use within the UK public sector.

Data standards within this architecture are defined at the business level in the Data Standards Catalogue (follow the links at http://www.govtalk.gov.uk/interoperability/eservices.asp?order=title) and at a technical level in accompanying schemas. This is very much a work in progress, and new definitions are being added as they are agreed across Government. As in most countries, the definitions that people need first surround names and addresses. In the UK, we do not have the luxury (from an interoperability view) of having unique citizen identifiers or a national name and address database, so most messages passed between citizens, businesses and public sector bodies will involve names and addresses, and it is important that these are well defined and unambiguous. These were therefore the first common schemas to be developed (they can be seen at http://www.govtalk.gov.uk/interoperability/draftschema.asp) and they are now being used extensively during their six month trial period.

On the metadata side, the UK Government has been working with the European Managing Information Resources for e-Government (MIReG) project to add public sector specific extensions to the Dublin Core. The UK now has a draft metadata standard (http://www.govtalk.gov.uk/interoperability/metadata_document.asp?docnum=460). This will be supplemented by local metadata standards for different uses and defined ways of representing the metadata. For example, web sites could have their metadata stored in HTML <META> elements. The first local metadata standard is for XML schemas and is, naturally enough, expressed in XML and defined in an XML schema.

As well as a description of the high-level architecture, the e-SDF contains rules to help with process interoperability. These centre primarily around the concept of re-usable business patterns and re-usable technology patterns. For example, a business pattern could be defined to validate a user by comparing a digital certificate against a certificate known to be held by the owner of a specific identifier (such as a National Insurance Number). Once defined, this process can be generalised to include other identifiers, registered with the Government, and then re-used by others needing to build this service into their systems.

Once this service has been defined as a business pattern, a Simple Object Access Protocol (SOAP) service could be developed to implement this as a re-usable technology pattern and the accompanying schemas registered.

These patterns and schemas are registered through the UK GovTalk^TM web site, which is a library, repository and discussion forum designed to support schema developers. This site, at http://www.govtalk.gov.uk, is the main support resource for those developing e-services for the UK public sector.

Currently, the e-SDF Primer is the only document supporting process interoperability. However, SOAP, Web Services Description Language (WSDL) and Universal Description Discovery and Integration (UDDI) have been flagged as a future direction in the e-GIF, so there will be a lot of progress in this area over the coming months.

The physical infrastructure supporting the e-GIF is shown in the diagram below. It is designed to provide portals for citizens and businesses to access Government services (the UK Online Citizen and Business Portals) and a central service to provide security and routing for these services (the Government Gateway). The citizen portal is now in its second generation, and the Gateway will shortly also receive a major upgrade.

The diagram shows access to public sector services starting at the top with the citizen or business requiring access. This person can use a variety of access devices to reach either a public sector site (such as the portals mentioned earlier) or a private sector portal such as ihavemoved.com where this has arranged to provide Government services. The conversation will generally be interactive and will use standards defined in the e-GIF.

The interaction might require identification of the citizen. In this case, the Gateway can provide identification services, using a credential such as a user ID and password or digital certificate to provide the front-end system with a suitable identifier for the individual or business involved. For example, a company accessing a web site to file a Value Added Tax (VAT) return will present a digital certificate, and the web site will send this to the Gateway and get a VAT reference in return. This VAT reference can then be used for purposes such as providing historical information or pre-populating a form.

At some point, a secure message might be sent to one or more public sector systems. In this case, the message, with an embedded credential, will be passed to the Gateway. This will use the credential validate that the user is entitled to send the message on behalf of the entity identified in the message. For example, I could send a VAT return on behalf of alphaXML, but not on behalf of Microsoft. If it is satisfied with this, it will pass the message over a secure link to the relevant public sector organisation or organisations. If the message is signed (which is a requirement in some cases), it will check the validity of the signature before routing the message.

In some cases, the interactive part of the system is bypassed. Returning to the VAT example, if a business uses a suitable enabled accounting system, this system could prepare the VAT return and send it directly to the Gateway. The UK Government has worked with several Independent Software Vendors to provide such additions to their systems.

What of the future of these systems? The portals will be continually upgraded to provide access through a wider range of channels to more public sector systems to meet the Government's aim of making all services available online by 2005. More work will be done with the private sector to make Government appear as just another provider of services. And the Gateway will receive a major upgrade this summer to move it to a web service architecture using the standards that will shortly be included in the e-GIF.

The e-GIF itself will continually evolve to ensure it retains its relevance and steers e-Government in the right direction. The UK GovTalk^TM site will provide more, better and more easily accessible information for developers. A registry for schemas will be setup, along with the tools required to support web services. More use will be made of the metadata that is now being included in documents to provide indexing and searching of Government information.

So although a lot has been done, there is still a great deal of work before we forget the term e-Government and this all becomes a standard part of the way that Government transacts its business with the citizen.