The British government needed to investigate the disclosure of secret information relating to Chinese telecoms company Huawei because it came from a classified intelligence briefing, the prime minister's spokesman said on Thursday.
Prime Minister Theresa May fired her defence minister Gavin Williamson on Wednesday over the leak from a meeting of the National Security Council (NSC) which discusses intelligence coordination and defence strategy.
"The prime minister is clear that the protection of information on matters of national security is of the highest importance. It is vital that ministers can receive briefing on security matters and that the security of this information is protected," the spokesman told reporters.
"This was not about what was leaked, it was about where this was leaked from, and the importance of maintaining trust and the integrity of the National Security Council."