The latest beta version of Yahoo Mail, a free, browser-based email service, began UK testing today.

Billed by Yahoo as "the most significant enhancement to the the Yahoo Mail interface since its launch in 1997", additions to the service include an integrated RSS (RDF site summary) reader.

The service is available to Yahoo Mail users in the UK and Ireland as well as France, Germany and Korea. Once the beta testing has been finished it will be open to Yahoo Mail users worldwide. No time frame has been set for global rollout, as it will depend on user feedback, according to Yahoo.

Eileen Broch, director of communications products, said: "This beta gives people a faster and more dynamic way to experience Yahoo Mail, yet continues to offer the same features they rely upon today. Great antispam and virus protection, tons of storage: it's all there."

The beta version offers users up to 1GB of storage space – no more than was available previously, and still over 1.5GB shy of the space on offer to Google's Gmail users. Yahoo currently offers a service called Yahoo Mail Plus, which provides up to 2GB of storage space, but it costs $20 (around £11.50) per year.

Other improvements to Yahoo Mail include an enhanced search facility and tabbed navigation to allow users to compose more than one email at a time.

Closed beta testing on the service has been taking place in the US for the last month. Rolling out the service in the UK will open it up to 4.9 million more users. There are currently 300 million Yahoo Mail users worldwide.