This thesis studies how Liberal Democrat members and supporters use Internet tools to mobilise volunteers within local election campaigns. It also identifies who is most likely to use these tools and who is most likely to perceive that they are useful. Existing studies of the use of Internet tools to mobilise volunteers are limited because they have typically focused upon the Internet-as-a-whole, instead of breaking it down into smaller, more meaningful categories. It is important to study Internet tools individually as they each have different features and some are more deeply integrated into mobilisation practices than others. Therefore, this thesis addresses this limitation by focusing upon three specific Internet tools: Facebook, Twitter and email. It uses data generated from a participant observation, survey and series of semi-structured interviews. Similarly, few studies have been carried out in England or within the context of second order elections. As a result, this thesis explores the perceptions of grassroots activists in relation to English local elections, thus offering a relatively unique perspective upon the link between Internet tools and volunteer mobilisation. The findings confirm that it is beneficial to analyse Internet tools individually because there are significant differences in how they are used, in addition to who uses them and who perceives them to be useful. Email is the most commonly used; it is also perceived to be the most useful for mobilising volunteers and increasing membership. Younger people are more likely to use Facebook and Twitter and to perceive that they are useful tools, whereas older people are less likely to do so. This emphasises the importance of younger supporters, as the party would find it more difficult to reach online audiences without them. This thesis argues that people that become involved as a result of Internet tools are less likely to remain heavily involved over the long-term. For instance, externally elected public officials are less likely to join online or use Internet tools to mobilise volunteers and increase membership. This fits with a wider pattern of engagement amongst party elites and long-term members. It emphasises the importance of using a combination of online and offline tools to mobilise volunteers and increase membership.