Official documents which describe how British forces were ordered to use mustard gas against Iraqi dissidents, including Kurds, after the first world war were removed without explanation from the public records office in 1992, around 13 years after they had been routinely declassified after 50 years of secrecy.
In 1993 newly declassified documents led to accusations that UK officials may have suppressed information to avoid embarrassment over their policy towards Jewish refugees during World War II. The UK authorities had access to speeches by Göbbels specifically referring to the annihilation of the Jews in Germany.