The rocky passage of much of Labour's welfare legislation through parliament raises important questions about the extent of parliamentary support for the government's reform agenda, particularly related to welfare. It is far from clear that Labour's welfare reforms enjoy widespread parliamentary support, even on the government's own benches. Some indication of the extent of discontent among Labour MPs may be gauged by the scale and frequency of rebellions by Labour MPs on welfare issues, most notably over cuts to Lone Parent Benefit, pensions reform, the creation of foundation hospitals and successive attempts to reform Incapacity Benefit. However, while it is clear that a significant proportion of Labour MPs have been sufficiently exercised by various aspects of welfare policy to set aside party loyalty and vote against the government, what is not clear is the extent to which such backbench rebellions are indicative of a wider disquiet on Labour benches.

Conversely, while analysis of backbench rebellions highlights opposition to Labour policies, it is less helpful in explaining the extent of parliamentary support for the government's reform agenda. Despite substantial rebellions on certain aspects of welfare legislation, party cohesion remains a defining feature of parliamentary life. Cowley suggests that the broad agreement of many Labour MPs with the reform agenda of the leadership may be explained, at least in part, by a shift in political attitudes in The Labour Party (Cowley, 2002). However, the evidence for such a shift in Labour MPs’ attitudes is not clear, and certainly can not be deduced from voting behaviour alone, which may be affected by other factors such as the threats and rewards offered by the Whip's Office. In order to determine whether there has been a genuine shift in the political attitudes of Labour MPs one must make a more forensic analysis of MPs’ attitudes and the extent to which they correspond with party policy, and moreover, whether these views are noticeably different from those expressed by Labour MPs in the past.

Looking beyond the voting behaviour of MPs may be even more important in establishing the opinions and attitudes of MPs in opposition parties. Given that most legislation presented to parliament is government legislation, one would generally expect the voting of opposition MPs to reflect opposition to that legislation. However, voting against the government tells us little about opinion within the other parties (although voting with the government may tell us a great deal).