Carbon nanotubes (CNTs) are very promising materials for the construction of strong fibres with very high specific and, in principle, absolute electrical and thermal conductivities. Whereas isolated metallic single wall CNTs are perfect quantum conductors, with a resistance that is independent of their length, those in a real fibre will be a mixture of semiconducting and metallic tubes with finite length, requiring electrons to tunnel through junctions between bundles in order to pass current along the fibre. To produce a fibre with a specific electrical conductivity exceeding that of copper, it will be necessary to control the distribution of chiral angles (i.e. the metallic versus semiconducting character) as well as maximising the lengths of the CNTs produced during synthesis process. The next stage will be to optimize the microscopic structure of fibre so as to maximise the potential for achieving ideal conductance behaviour of the individual tubes. In this project, we will use a combination of molecular, mesoscale and finite element approaches to meeting these challenges, in conjunction with parallel experimental investigations.