The conspiracy prevention operation lasted for several weeks, involving MI-5, Scotland Yard and the police.
A man died in a terrorist incident at Finsbury Park mosque in north London in the same month - and, in September, an attempt to bomb a Tube train at Parsons Green station failed.
The two men who were arrested on November 28 for the foiled plot are Naa'imur Zakariyah Rahman, 20, of north London, and Mohammed Aqib Imran, 21, of Birmingham, according to a Metropolitan Police news release. The report said British security forces had missed chances to stop the attack. Four have been successful, including the May attack that killed 22 following an Ariana Grande concert at Manchester Arena.
Stringent protective measures were first put in place in the 1970s, and were tightened during the 1980s when Irish republicans launched attacks on the British mainland.