The assassination of Iran's most powerful military commander took "everybody by surprise", according to former defence minister Tobias Ellwood.
Qasem Soleimani was killed at Baghdad airport on January 3 in a drone strike ordered by Donald Trump.
The US president said the general had been "directly and indirectly responsible for the deaths of millions of people", but Iran has vowed "severe revenge" following his death.
Conservative MP Mr Ellwood said he was expecting an act of retaliation following the attack on a man he described as a "pivotal, totemic character".
"Let's not forget who Soleimani was. Most of the world perhaps wasn't aware of this person being one of the most powerful men in uniform in the Middle East," he said.
"It is difficult to think of another character that has been so divisive, so when the opportunity came - because apparently an attack was imminent - the Americans took the shot."
Mr Ellwood said the UK had already made moves to protect holidaymakers and embassies as tensions rise following the air strike, with Boris Johnson calling on Iran to "refrain from further violent action".
"We are expecting reprisals and we have taken the necessary measures to make sure our embassies, our military personnel, tourists and other commercial operations are as safe as they can be," he added.
"The question is with this removal, is this an opportunity for us to re-engage and be less risk averse? And to stand up to countries such as Iran that have an interventionist foreign policy that has sowed so much division all the way up to the Mediterranean."