Escript has been designed to give modellers an easy-to-use environment for developing and running complex and coupled models without accessing the underlying data structures directly. This approach leads to highly portable codes allowing the user to run a simulation on her/his desktop computer as well as highly parallel supercomputers with no changes to the program. Escript is suitable for rapid prototyping (e.g for a student project or thesis) as well as for large software projects. It has successfully been used in a broad spectrum of applications including Earth mantel convection, earthquakes, porous media flow, reactive transport, plate subduction, and tsunamis. Escript uses the finite element method (FEM). The code has been parallelized efficiently with MPI, OpenMP and hybrid mode. The Escript download page can be found at https://launchpad.net/escript-finley.