Summary and implications

The European Patent Office Technical Board of Appeal has ruled on what is increasingly an important component of the evidence forming prior art attacks, namely alleged disclosures by email.1 The precedentconferring status of the TBA means that this is a significant decision both for EPO oppositions and for litigation in national courts across Europe.

The TBA has held that contents of an email do not automatically become publicly available and form part of the prior art as a result of the transmission of the relevant email. This is irrespective of whether the email was encrypted or not, and of whether or not the emails were publicly available because they could have been lawfully intercepted by an internet service provider or by law enforcement personnel.

Whilst the TBA’s conclusion is not altogether surprising, the decision has potentially significant strategic implications for both EPO oppositions and for patent litigation in Europe.

  • Emails have equal status with other types of disclosure, and are as potentially an important basis for attacks on patents’ validity as any other type of document.
  • If information can be publicly accessed by ordinary online means it will be considered to be part of the state of the art. If this is not the case, for it to be prior art it must be demonstrated that the information has been accessed and disclosed to the public at least once.
  • The decision places a premium on a proper analysis of the probative value of the contents of emails, their character, and the extent to which they are confidential or may have been made public. Cogent evidence will be required to establish that - on the balance of probabilities - an email was accessible by a member of the public who was not under an obligation to keep the contents of the email secret.
  • Given that emails are normally in the power and control of the sender and recipients, and that most European countries have no discovery rules, parties engaged in strategically important European patent disputes should be alert to the possibilities of using formal discovery from the US or England to force opponents or relevant third parties to disclose this type of material. Parties engaged in parallel US litigation should be particularly alert to the possibilities of deploying US discovery in this way.


Under the European Patent Convention an invention must “not form part of the state of the art” if it is to be considered new, and therefore be patentable. Article 54(2) EPC provides that the state of the art comprises “everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application”.

In this case, the entire outcome of the opposition turned on whether certain emails transmitted before the filing date should be treated as prior art. If they were, then it was accepted by the parties that the opposition would succeed given that these disclosures contained novelty-destroying material. There were two emails in question, one of which had been encrypted and one of which had not.

Under EPO case law information is “available to the public” if only a single member of the public is in a position to gain access to it and understand it, and if the disclosure to that member of the public is not under an obligation to maintain any secrecy.2 It is irrelevant whether or not a member of the public has actually accessed the information.3

The TBA emphasised the basic factual difference between content on a web page on the internet and content that is transmitted over the internet by email. Web content can in principle be accessed via electronic “pull type” technology (i.e. where the request for a transaction is initiated by the receiver) and read via its URL, which can be found by members of the public with a public search engine if the particular content has been keyword indexed.

In contrast, an email is a private communication from a sender to one or more recipients transmitted over the internet via electronic “push type” technology (i.e. where the request for a given transaction is initiated by the sender). Emails are not placed in an open and unrestricted area of the internet, cannot be located by using public search engines, and can only be read by a member of the public (who is not a recipient of the email) if extraordinary measures are used, such as deliberately intercepting or hacking a computer network.

The decision – parallels with web-based disclosures

The test established by the TBA in case T 1553/064 for whether a document was made available via the internet to the public in the sense of Article 54(2) is whether before the relevant date a document stored on the internet and accessible via a specific URL –

“(i) could be found using a public web search engine by using one or more keywords all related to the essence of the content of that document, and

(ii) remained accessible at that URL for a period of time long enough for a member of the public, i.e. someone under no obligation to keep the content of the document secret, to have direct and unambiguous access to the document.”

The TBA re-emphasised the applicability of this test. The mere theoretical possibility of having access to a document on the internet did not automatically make it become available to the public within the meaning of Article 54(2) EPC. More was required. There had to be a practical possibility of having “direct and unambiguous access”.

The TBA held that the technical and factual differences between webpages and emails meant that there was a strong prima facie case against any finding that emails transmitted via the internet can reasonably be said to be publicly available in the same way that webpages can be. The TBA doubted that emails transmitted over the internet could be accessed and searched in a way comparable to webpages, independently of whether or not access to and disclosure of the content of such emails was lawful.

Specifically, the TBA held that the legal test of access by “a member of the public, i.e. someone under no obligation to keep the content of the document secret” would not be met by an email transmission via the internet.

The effect of potential interception of an email

The opponent’s main argument was that, as a matter of fact, email interception routinely takes place in the US and that emails can be fully keyword searched in the US. It therefore argued that US emails – including those transmitted via US servers (including .com addresses) irrespective of the country of origin – were to be treated as being public as they were open to lawful interception by an internet service provider or by law enforcement personnel. This factual matrix is unique to the US as intercepting emails sent or routed via European countries is illegal as a matter of EU law.

The TBA ruled on both the position in the EU and in the US:


The TBA held that it was clear that any potential interception of an email in the EU would be unlawful as a matter of EU law. The result was therefore that the test established in T 1553/06 would not be satisfied in the case of emails sent via the internet in the EU. There would be no access by a member of the public who was not under an obligation to keep the content of the email secret.


The TBA was not satisfied that as a matter of fact wholesale email interception was occurring in the US and was lawful in a way which made the contents fully public in the sense required by the test established by T 1553/06. Even if this were the case, the TBA would not accept that an intercepted email could be used in a novelty-destroying way in patent proceedings in Europe. This would be contrary to EU law, which expressly provided that private communications over public telecommunications networks were confidential and were not to be intercepted. It would also be contrary to the fundamental right to the protection of private life and correspondence enshrined in Article 8 of the European Convention of Human Rights.

Even on the assumption that US ISPs and law enforcement agencies were lawfully entitled to intercept emails transmitted over their networks in the US, an email passing through the US does not become publicly available for that reason alone. It is still necessary to prove a specific instance of disclosure of that email. The mere potential for disclosure in the US was not sufficient. The emails were not therefore considered to be prior art.