The association was formed in 1979 to give a focus for private sector businesses in land and hydrographic survey. It is important to realise, however, that it is not a regulatory body. The role of TSA is to promote best practice amongst its members, provide a forum for members for discussion, debate and continuing professional development and, to the wider audience such as engineers and architects, provide guidance on new methods and techniques and a list of suitably qualified and experienced companies. Today, the association has over 185 companies in membership as full, associate, supplier, affiliate or academic members directly involved in the survey business. TSA is also heavily involved in lobbying Government and other agencies such as the Environment Agency regarding policies likely to affect or involve the survey industry. TSA meets regularly with RICS and Chartered ICES on a range of issues and has established a group called the SLG, or Survey Liaison Group. This body convenes at regular intervals to examine matters of mutual interest and to ensure that there is little or no duplication of effort by the three bodies.