The JET Joint Undertaking was established in 1978 to construct and operate the Joint European Torus (JET) at Culham in the UK. JET is the world's largest fusion experiment funded and staffed by the EU member states and Switzerland. Its aim is to prove the scientific feasibility of nuclear fusion as a new energy source. A major component of the JET machine is a large (200m3) toroidal vacuum vessel whose interior is subject to regular modifications and upgrades. The installed equipment has increased in quantity and complexity while the working environment has deteriorated due to increasing radiation levels and the presence of highly toxic beryllium dust. Progress in plasma physics has led to a requirement for much improved alignment accuracy. This paper describes the evolution of the survey and alignment methods used to accomodate the requirements of increased accuracy and complexity and the wearing of full pressurised suits. The ultimate aim is to carry out checking surveys remotely to an acceptable tolerance.