The satellite, called the ExoMars Trace Gas Orbiter (TGO), lifted off from Baikonur in Kazakhstan at 09:31 GMT.

The probe will investigate whether the methane in the world’s atmosphere is coming from a geological source or is being produced by microbes.

If all goes well, the two space powers expect to follow up this venture with a rover, to be assembled in the UK, which will drill into the surface.

That could launch in 2018, or, as seems increasingly likely, in 2020.