There is very strong evidence of Israel's culpability. This is simply diplomatic language. UK is more polite than Israel and does not wish to unduly embarrass a rogue regime that promised them yrs ago when they were caught doing the same thing that they would not do it again. Redux.
U.S. asks Uzbekistan to join anti-ISIS coalition (Reuters)
from the article: U.K. officials were split over expelling Israeli in Dubai row