Ideology defined the general elections of the 1970s and 80s. Unilateralism, privatization and the power of trade unions all represented clear blue water between the Conservatives and Labour as each headed away from the centre ground they had traditionally competed on for more than three decades.
You could be forgiven for thinking that ideology has all but disappeared as today's main parties square up for the General Election on May 7. Both Tories and Labour are committed to updating Britain's nuclear deterrent, the renationalisation of privatised industries is not on the agenda and handing power back to the unions is a subject never spoken about by Ed Miliband.
Instead, the two main parties trade blows on the NHS, immigration and the budget deficit. The electorate could be forgiven for thinking that it would be hard to get a piece of paper between David Cameron and Miliband, let alone find blue water.
But Britain's continued membership of the European Union does remain a clear dividing line between the two main parties. The Prime Minister has committed to an in/out referendum by the end of 2017, while Labour has ruled out a plebiscite. Ed Miliband used a speech to the Confederation of British Industries (CBI) to warn that the planned referendum is a recipe for chaos and puts Britain's exporters in grave danger.
It is very early days but until last week, Britain's future in Europe had received relatively little election coverage by both traditional and social media. There was a jump following the speech but Miliband may struggle to ignite it as a central theme for the wider electorate beyond the business community. The Tories are receiving more than 33 per cent of election attention, Labour 28 per cent and UKIP a little over 17 per cent.
When Parliament dissolved, coverage slumped across the board but with the Conservatives suffering far more than Labour - falling from more than 8,000 articles focusing on them the week before to just 1,372. Labour's media profile was marginally ahead for the first time since mid February, perhaps reflecting the wide trailing of Miliband's speech later that day.
Cameron may well attempt to squash Labour's attempts to elevate Europe to one of the main themes of the election by arguing that this is precisely why he has committed to an election. He will also want to do as much as possible to neuter the threat from UKIP which has, since early February, consistently received more coverage than the Liberal Democrats and briefly overtook Labour in mid March.
Like the polls, which continue to suggest no one party gaining an overall majority on May 7, coverage has swung back and forth with Labour and the Conservative trading pole position since our surveys were launched at the end of last year.