The Future Offensive Air System was a study which sought to replace the Royal Air Force's strike capability currently provided by the Tornado GR4. Initial operation capability was expected around 2017. In June 2005 the study was cancelled. ^*

The capability required may have been provided by any number of systems;

• New build aircraft, for instance the BAE HALO or BAE Replica demonstrator (see image)
• Development of current aircraft:
  • Eurofighter Typhoon - with increased internal fuel capacity and possibly internal weapons carriage.
  • F-35 - most likely the CTOL version (F-35A)
• Unmanned aerial vehicles (UAVs)
• Standoff missiles (Storm Shadow)
  • From next generation strike aircraft
  • Possibly from large, cheap non-penetrating aircraft (Airbus A400M)
• Mix of above systems

It seems likely that the United Kingdom would seek to procure such a system in collaboration with another nation; the country with the most similar requirements is perhaps France, which maintains a similar expeditionary strategy for its military. However, the Royal Air Force has been cooperating with the U.S. Department of Defense on the F-35 project, and it is currently the favourite (per industry trade magazine Aviation Week & Space Technology) for UAV/UCAV cooperation as well, given the American lead in unmanned aircraft technology.