TV Guide BBC Four Wednesday

The mountains and forests of northern Thailand, an area that is home to a variety of wildlife, leading to unusual partnerships developing between animals and people. Narrated by Sophie Okonedo

Exploring the realm of the creatures to better understand how they have evolved. Travelling from the rain forests of French Guiana to the Arctic Ocean, scientists use traditional and cutting edge techniques to examine both modern insects and the fossil record in their search for a single common insect ancestor

Documentary following the construction of a 36,000 tonne steel structure to entomb the ruins of the nuclear power plant destroyed in the 1986 disaster. A team of international engineers race to build the new steel structure, but radiation levels make it almost impossible for workers to build right on top of the old reactor. The team face difficult challenges as they attempt to erect this new steel mega-structure and move it into place

Smiley seeks out an invaluable friend as he tries to procure the information and files needed to conduct his investigation. Meanwhile, Peter breaks into the Circus's archives. Espionage drama from 1979, starring Alec Guinness, Beryl Reid, Michael Jayston and Ian Richardson

George Smiley recalls his involvement with Tinker, Tailor, Soldier, Poorman, and remembers Karla, the legendary head of the Moscow Circus. Classic espionage drama from 1979, based on the novel by John le Carre, starring Alec Guinness, Michael Jayston and George Sewell

Having realised that Source Merlin is run by Karla from Moscow Centre, George Smiley decides the time has come to call on Jim Prideaux. Fifth part of the classic 1970s espionage drama, based on the novel by John le Carre, starring Alec Guinness, Michael Jayston and George Sewell