Certainly the UK and US would have known about the operation to take out Nasrallah, or even actively colluded by helping provide his location. Israel is not generally a rogue state (though it is often a liability with some of the more reckless actions it takes), it is the attack dog of a powerful larger system and ther
Certainly too by Mossad, here is a SOTT article from 2005. And I think it could be expected that Hezbollah has been infiltrated for long.
Damascus: Syria's official Al-Thawra newspaper claimed Thursday that more than 400 agents from Israel's spy agency Mossad are in Lebanon in the latest volley in an increasingly vitriolic war of words with Lebanon's new leaders.
"You have to recognize the danger of having more than 400 men from Israel's Mossad in Lebanon who are working with the other (Lebanese) agents who once supported the Zionist enemy and its militias," wrote editor Fayez Sayegh
"These agents are encircling Lebanon like a belt that will explode when Israel and its strategic ally, the United States, decide," he said, charging there was also an increasing number of agents from the CIA and European states in the country.