Tim Peake rehearses for spacewalk in a huge swimming pool

Tim Peake is to carry out the first ever spacewalk by an "official" British astronaut, alongside Nasa astronaut Tim Kopra, on 15 January to replace a failed voltage regulator on the International Space Station.

While Major Peake has said he is keen to do a spacewalk, he admits it is one of the three high-risk activities that astronauts under take.

The BBC Horizon programme filmed his spacewalk rehearsal - which involved at least four hours deploying cables in a giant swimming pool.