Hydralock Systems Limited (HLS) will undertake a project in order to prove the enabling concept technologies which will allow for the development of a downhole tool actuator device for the Oil and Gas industry. Downhole tool actuators face several inherent problems which the project intends to address. Namely they are: the delays incurred whilst waiting for the actions of the operator at surface, to operate the actuator in question; the potential restrictions caused by the introduction of external objects to the mud flow, the requirement to break connections in order to introduce objects whether they are balls, darts or RFID tags; the potential risk of existing devices to hang up in Extended Reach Development (ERD) wells; and the limited number of activations for any current tool. The directors have established a concept which simultaneously addresses these issues. Namely a hydraulically lockable actuator mechanism mounted in a sub-based tool, controlled by a pressure sensing electromechanical logic system. On receipt of a pressure signal from surface, the logic system opens or closes a valve, allowing the tool to actuate. To reach the stage where a prototype tool can be commissioned, the company must first prove the feasibility of the component concepts which underpin the overall design. Though the concept has many applications, the company will initially focus development efforts on side-port circulating subs. This project will last 12 months and be delivered for a cost of £165k. This project allows the early applied research to be undertaken which precedes a short development phase to give HLS access to this potentially lucrative market. From an early development stage (month 10 of this proof of concept plan) end users will have details of the development disseminated to them in order to realize the potential usability of the technology after it has completed this post project development. This will allow HLS to maximize the market opportunity.