UKELT: The next generation instrumentation suite for the Extremely Large Telescope

The Extremely Large Telescope (ELT) is the world's most ambitious ground-based optical-infrared astronomical facility. The innovation in the telescope's design is only matched by that of its instrumentation suite. The UK ELT Programme was set up to deliver a sequence of key contributions towards the development of ELT instruments aligned to the broad scientific priorities of the UK astronomical community for the coming decades. In this Preliminary Activity we propose essential design work and prototyping towards the next generation instruments for ELT: the multi-object spectrograph (MOSAIC); the high-resolution spectrograph (ANDES); and the planetary camera and spectrograph (PCS). These instruments, with distinct and novel capabilities, will be able to address fundamental open questions with implications beyond astrophysics, such as the search for signs of life (bio-signatures) in the atmospheres of planets outside our own Solar System (extra-Solar planets or exo-planets) to test whether the accepted fundamental constants of Physics vary over space and time.