British internet users will be able to download the latest version of the Mozilla Foundation's Firefox browser this evening.

Improved security will be a key feature of the lastest release, with better pop up blocking and a Clear Private Data function that allows users to quickly remove personal data through a menu item or keyboard shortcut. The coding has also been tightened to eliminate known security holes.

Other features include an improved updating system, faster navigation using the 'Back' and 'Forward' tabs, and a redesigned Options/Preferences window that increases the number of category icons.

Tabbed browsing should also be updated to include boxes to close tabs and the option of opening all links in tabs rather than new pages. Increased support for the visually impaired is also expected.

Firefox 1.5 also adds support for Scalable Vector Graphics (SVG), JavaScript 1.6 and version two and three of CSS (Cascading Style Sheets). Support for search engine Answers.com has also been added.

The Mozilla Foundation is expected to put a major marketing push behind the new code to increase its market share beyond the current level of around 11 per cent.