It was not immediately clear whether the security agencies would lift all restrictions on the movements of the 72-year-old metallurgist, who has been treated for prostate cancer…

Last year a UN nuclear watchdog said Khan’s network smuggled nuclear blueprints to Iran, Libya and North Korea and was active in 12 countries. Last month the US state department imposed sanctions on 13 individuals – two of them British – and three private companies because of their involvement in Khan’s network.