We have seen that, with the change from mass membership to catch-all parties, the political science view is that election campaigns have shifted from mobilizing supporters to persuading voters:-
The election campaign is Britain is fairly short, with as little as 17 days between the dissolution of Parliament and the general election day. There is a little flexibility for the Prime Minister to make it longer.
Mrs Thatcher thought that three weeks was quite long enough, though she expected to win, while John Major and Gordon Brown chose slightly longer campaigns hoping they could recover ground in the campaign but without success.
The Electoral Registration and Administration Act, 2013 increases the minimum time between dissolution and the election to 25 days.
The political parties concentrate on promoting the issues that they ‘own’. The evidence, though, is that this does not necessarily change the issues that the public think are important, although the parties will have checked the salient issues in their opinion polling and focus groups and will shift their appeal accordingly.
Sometimes parties cannot ignore issues that are salient even if they do not own them, as with Labour over immigration in 2005 and 2010 and the Conservatives over the NHS in all the last few elections.
Parties will look to get their agenda and their messages across through the national media and also target swing groups of voters in the marginal constituencies that will decide the election.
The campaign can have an effect on the outcome as some 40% of voters say, at the beginning of the campaign, that they have not decided who they will vote for, possibly an effect of the decline in partisan attachment. This has been intensified by the introduction of TV debates featuring party leaders; the performance can sway voters too as seen by the increase in the Liberal vote in 2010.
In 1997 and 2001, Labour lost some of its commanding lead; in 2005 the Conservatives lost about 3% of the vote and the Liberal Democrats gained 2% with Labour steady.
In 2010, the Conservatives about 1% and the Liberal Democrats gained 3%, with Labour making no headway. The Liberal Democrats normally get much less publicity than the other two parties between elections and so the campaign, when media attention is more even, has been especially important for them, this was different in 2015 as they had the publicity of being a governing party.
The national campaign and individual constituency campaigns are not independent. Some of the literature used locally will convey the national messages and, although blanket canvassing on foot or by telephone and leafleting still happens locally, there is now much more use of target letters and emails to voters on particular issues based on the information that the party has about them. Justin Fisher, David Cutts and Edward Fieldhouse have shown that, using an index of intensity of constituency campaigning, local party activity does affect the vote (Electoral Studies Vol 30 No 4, 2011).
Although Labour in 2010 did not improve its national vote during the campaign, it did perform better in the marginal seats it already held, probably because of the advantage of an incumbent MP and the intensity of local campaigning.
There will always be local issues in a constituency, for example, the mothballing of the Corus steel plant with the loss of 1600 jobs undoubtedly contributed to Labour losing the normally safe seat of Redcar to the Liberal Democrats in 2010.