The role of Prime Minister has been constantly evolving over the years, and it can be argued that the degree of power he/she wields changes with it. For example, during the late 17th century, a Chief Minister existed as a special advisor to the monarch. However by the late 19th century, the Prime Minister is the leader of the largest party of House of Commons and enjoys greater political power, whereas the monarch acts as Head of State.
It is logical to assume that a Prime Minister’s degree of power will be very dependent on the size of majority his party enjoys in the House of Commons. In the case of Blair, he enjoyed a very large one, with 63.4% of the seats filled by Labour MPs. Since the party won the right to govern, the Prime Minister carries all the elective authority with him. Also, with little opposition, it allows the Prime Minister to exercise his powers more efficiently, which would undoubtedly be very helpful when wanting to pass new laws. Cameron in turn, should expect to enjoy less power as he had to form a coalition government with the Liberal Democrats, in order to achieve a majority. This would mean that the likes of the Prime Minister would in many situations have to be compromised.
Another essential factor which would influence the degree of Prime Ministerial power is the unity of the ruling party or coalition. In Blair’s situation, he enjoyed an exceptionally united group, therefore being able to enjoy several years of complete domination. When Blair resigned, Brown was said to enjoy similar power, at least when he still enjoyed popularity. Cameron on the other hand would expect less of this as he had entered a coalition from the very beginning, which suggests that the cabinet is naturally divided. With different ideologies, it is inevitable that there will be times of disagreements, which suggests that he would