The future of interferometry in Europe in the next decade will be addressed in the context of other European and worldwide ground infrastructures such as ALMA, the E-ELT/TMT and SKA and space infrastructures such as the GAIA satellite as well as emerging optical interferometers in the USA such as the Large Binocular Telescope Interferometer and the CHARA and MROI arrays. This working group will involve major players in optical interferometry as well as members from the community at large. This new working group will build on the scientific reports delivered by the previous working groups focused on circumstellar disks and planets and on the galactic centre and extragalactic science.