Cabinet: Directorate or Directory?

In his second Reith Lecture entitled 'Cabinet: Directorate or Directory?', Sir Douglas Wass dissects the composition of the British Parliamentary Cabinet to answer the questions; how well does it do its job? And could it be more effective? Sir Wass analyses that the British Cabinet is filled with high ranking parliamentary ministers who very rarely function as a collective group. He claims this is because each have their own proposals that they wish to promote and so they work as a group of individuals rather than a community of decision makers with a collective responsibility. He explains how this often can lead to stagnation and an abstraction of policy that cannot be put into practice. How can we increase cohesion in the Cabinet?