The LTBT was drawn up by the USA, Britain and the USSR subsequent to the increased understanding of the dangers of nuclear fallout.
It was agreed not to carry out any nuclear weapon test explosion or other nuclear explosion 'in the atmosphere', under water or in outer space
Additionally testing could not be carried out in any other environment in which the radioactive debris could become present outside of the borders of the state conducting the explosion.
After 1963, a further 113 countries signed the treaty
The Outer Space Treaty
This stopped the arms race extending into space and also set out that no nation could 'claim the moon'.
Drawn up in 1967 by Britain, the USA and the USSR and stated:
Exploration of space should be carried out for benefit of all countries
States should not place WMDs or other nuclear weapons in orbits/on planets
Moon and other celestial bodies should be used for peaceful purposes only
States are responsible for damage caused by their space objects
Harmful contamination of space and celestial bodies should be avoided
Signed by 12 other countries.
The Nuclear Non-Proliferation Treaty (1968)
This was signed by the USA, USSR, Britain and 59 other states.
It was divided into two categories:
Nuclear weapon states (NWS) such as the USA, USSR, China, France and Britain,
Non Nuclear weapon states (NNWS)
It stated that NWS would work towards disarmament and play no part in helping other nations to develop nuclear weapons
NNWS at the time agreed not to develop nuclear weapons, mostly because at this time they did not have the financial or technological abilities to do that anyway.