What are the features of cabinet committees?

PMs have the ability to reorganise the structure.
May streamlined the committee system she inherited from David Cameron – decided to scrap a number of long-standing committees, like the constitutional affairs and public expenditure committees, and has rearranged the remaining sub-committees around four main policy committees, all of which she chaired.
This signalled May’s intention to keep fully informed of policy developments, and to avoid surprises in full Cabinet meetings.

There are limits on how much power PMs are willing to delegate to committees.
For example, in 2011, the PM announced that he was pausing controversial NHS reforms, which were being developed by the Secretary of State for Health Andrew Lansley, so that the government could listen to the concerns being raised but by 2012, Lansley was reshuffled to a new post as Leader of the House of Commons.
Equally while Cabinet meetings officially signed off on policies, they were not necessarily the place where important coalition deals were made. Bilateral meetings between Cameron and Clegg were common, as were meetings of ‘the Quad’.

Cabinet became more influential under Theresa May.
It has been suggested that the reason why some of May’s preferred policies, such as her abandoned plan to put workers on company boards, have either been watered-down or abandoned, is that they were challenged in cabinet sub-committees.
some media commentators criticised May’s government for a lack of policy announcements, but others countered that if May is genuinely seeking to lead a cooperative cabinet government, rather than a more informal ‘sofa government’, then it is inevitable that decisions and announcements will take some time, particularly as May came into power quickly, without having to win either a general election or a vote of Conservative members.