If the UK had not played their part in the arming & training of dubious rebels groups, in hope of provoking regime change, then there would be no ISIS. Are we still repeating the mistakes of the past? There are indications that UK special forces have been on the ground fighting alongside the Muslim Brotherhood & al-Qaeda in Libya. The battles have mainly been concentrating on fighting ISIS in Sirte, effectively aiding one side in a terrorist power struggle, & expecting positive results.
An internal dispute within al-Qaeda over who would be the main beneficially of US coalition military aid in Syria, who would be the leader of a unified opposition, led to part of al-Qaeda breaking away from Ayman al-Zawahiri leadership, & forming al-Qaeda 2.0. ISIS. The London attacker is highly influenced by said terrorist groups, who’s rise can be linked to a poor UK policy of arming terrorists, in hope of provoking regime change, under the guise of humanitarianism, then having an open door policy where radical Islamists can enter the country &; influence others. What the UK government has called moderate rebels, have been groomed to kill secular citizens &; impose Islamic theocracy, it is culturally & quite possibly literally suicidal to be in favor of such policies.
When it came down to it the politicians who made the choices to aid the advance of terrorists in Libya & Syria knew the risks, they knew the huge potential for blowback, but they thought arming terrorists is worth the price. London attack: The victims
2011: British and French special forces are on the ground in eastern Libya, calling in air strikes and helping rebel units as they prepare to assault Sirte:
Then after helping ISIS capture Sirte the UK sides with al-Qaeda & the Muslims Brotherhood against ISIS. British special forces destroyed Islamic State trucks in Libya, say local troops
Concluding in blowback.