For reasons of national security minimal information about this engagement has been released by the government and we will not be informed whether section 7 came into play or not. The Prime Minister's statement to Parliament informs us that the strike was conducted by the Royal Air Force. The Attorney-General advised the government; the threat was identified by the Intelligence Service; the National Security Council met and the Defence Secretary authorised the action. In this context, the Prime Minister's use of the word "authorised" seems to simply mean that the Defence Secretary gave the go ahead to it as a military operation.
(1) If, apart from this section, a person would be liable in the United Kingdom for any act done outside the British Islands, he shall not be so liable if the act is one which is authorised to be done by virtue of an authorisation given by the Secretary of State under this section.
(2) In subsection (1) above “liable in the United Kingdom ” means liable under the criminal or civil law of any part of the United Kingdom.
(a) to obtain and provide information relating to the actions or intentions of persons outside the British Islands; and
(b) to perform other tasks relating to the actions or intentions of such persons. (Colour added).
(2) The functions of the Intelligence Service shall be exercisable only—
(a) in the interests of national security, with particular reference to the defence and foreign policies of Her Majesty’s Government in the United Kingdom; or
(b) in the interests of the economic well-being of the United Kingdom; or
(c) in support of the prevention or detection of serious crime.
A first point to note is that acts authorised under section 7 will not attract criminal or civil liability in the U.K. Section 7 is limited to acts outside the British Islands which are necessary for the proper discharge of a function of the Intelligence Service or GCHQ. The Act is silent as to who the individuals carrying out such acts might actually be.
The Intelligence Services Commissioner report for 2014 notes (page 23) that some non-governmental organisations have expressed concerns about the broad nature of section 7 authorisations and the fear that they may be used to permit SIS or GCHQ to commit serious offences. The Commissioner asserts that "this is not the case" because (a) the government (and not the SIS/GCHQ) decides the necessity of the intelligence required, (b) the Foreign Secretary decides if a proposed operation is both necessary and reasonable and (c) "SIS staff have no desire to operate unlawfully."
However reassuring that might be, it does not alter the point that the Act lacks limitations on the activities that could take place under a section 7 authorisation. The Commissioner's report has the effect of highlighting the point that, apart from his oversight of the Intelligence Services, any control is primarily political and the Secretary of State is accountable to Parliament and to the Intelligence and Security Committee.
The Intelligence Services Commissioner website gives more information about section 7 authorisations.
2013 report of the Intelligence Services Commissioner.