Google has just announced a new experimental feature for its search engine; as of tomorrow, anyone who signs up for it will be able to see relevant emails from their inbox alongside regular search results.

Naturally, the trial feature will only be available to Gmail users, who will be able to view their most relevant email results in a separate panel if they decide to opt in. Examples of relevant email results would be things like flight bookings and confirmations, and products bought online. Alternatively, a search online for “cycling in Amsterdam” would throw up any Gmail messages that contained these two phrases or mentioned cycling in the Dutch city.

Google, who said that the feature was part of the web giant’s plan develop a search engine of the future, is to roll out the trial this Thursday for Gmail.com users. To begin with, the feature will only be available to English speaking users.

Writing on Google’s official blog, search boss Amit Singhal explained the thinking behind the move:

“Sometimes the best answer to your question isn’t available on the public web – it may be contained somewhere else, such as in your email. We think you shouldn’t have to be your own mini-search engine to find the most useful information – it should just work. A search is a search, and we want our results to be truly universal.”

“So we’re developing a way to find this information for you that’s useful and unobtrusive, and we’d love your feedback. Starting today, we’re opening up a limited trial where you can sign up to get information from your Gmail right from the search box. These are baby steps, but important ones on our way to building the search engine of the future – one that is much more intelligent and useful than it was just a few years ago. It’s a very exciting time to be working in this field.”

No doubt Google will have to be careful where they go with this feature, having faced considerable scrutiny in the past about the privacy of some of its products, such as the now-defunct Google Buzz.

Nevertheless, the search engine giant seems determined to forge ahead with its plans. In a press conference on Wednesday, Google unveiled a voice-enabled search application to rival Siri, as well the inclusion of personalized results in its Knowledge Graph database, which currently contains more than 500 million entries about people and places, and how they are connected to each other.