What are constitutional conventions, their role, and effectiveness in the UK constitution?

Former Labour Party leader Jeremy Corbyn criticized then Prime Minister Theresa May`s decision to launch air strikes in Syria in 2018, stating, "I’m sorry to say that the prime minister’s decision not to recall parliament, and to engage in further military action in Syria last week, showed a flagrant disregard for this convention. It seems the convention established in 2003, and in the cabinet manual, is being tossed aside as simply being inconvenient."

In the context of the UK constitution, constitutional conventions are unwritten practices or understandings that guide the behavior of constitutional actors, such as the Prime Minister and Parliament. Despite not being legally binding, they play a crucial role in shaping the operation of the constitution by providing a framework for political behavior. Their effectiveness lies in their ability to facilitate the smooth functioning of the constitutional system, promoting accountability, stability, and the maintenance of key democratic principles.