The out-of-control Russian Phobos-Grunt spacecraft could crash land on southern England this weekend, scientists have warned.

The craft failed in its mission of gathering samples from the Mars moon it is named for, and is expected to explode as it enters the atmosphere.

The stricken craft could scatter debris over 200 kilometres, anywhere in a latitude band from the M4 corridor to the Falkland Islands.

Scientists across the world - including the RAF tracking station in Yorkshire, will track the craft and issue warnings as to where it is expected to land.

Professor Richard Crowther, chief engineer at the UK Space Agency, told Sky News the fragments are most likely to fall into the sea.

He said: "If you look at the Earth from space, most of it is covered by water.

"The UK is very small by comparison. The probability of it falling in such a small area is very, very low. It doesn't keep me awake at night."

It hasn't been a great run for the Phobos-Grunt. First its solar panels opened facing the wrong way, dooming its navigation system immediately.

The craft launched on November 18 2011 on a Zenit 2SB Rocket.

Once the rocket reached the "Low Earth Parking Orbit", further burners were meant to kick it out into space in an eliptical orbit of earth, before another burner would have taken it on to Phobos.

Neither of the two rocket burns worked, so the Phobos-Grunt stayed stuck in Earth's orbit.