The aim of any political party is to win power, yet judging by opinion polls no party at Westminster is likely to do so outright in May.

Recent announcements by the Scottish National Party and Democratic Unionist Party show that, given exceptional circumstances, often the objective of smaller parties can be to prevent larger parties from having their own way.

Following defeat in May’s general election either Labour or Conservatives will inevitably seek a new leader, whilst the appointed Prime Minister will occupy a poisoned chalice.

David Cameron or Ed Miliband will head the government, yes, but probably via a confidence-and-supply arrangement with smaller parties chopping, changing and approving the legislative agenda.

The resignation of Cameron or Miliband may be a personal tragedy from them, but perhaps not so much a disaster for their own party considering the loss will be a narrow one.

Rarely in British politics does a governing party boost its share of Westminster seats at the end of its term of office; given that the next 5 years look set to be dominated by a programme of austerity, if not managed correctly then the party that limps to victory this May might not do so again for a long time.

Defeats in politics happen for a range of reasons, but defeat could also offer the Conservatives or Labour a chance to rebuild, and ahead of 2020 develop and propose a tangible alternative to the personalities and platforms currently failing to grasp the public’s imagination.

Cameron recently alluded to high profile Tory MPs who could succeed him as party leader, and given Boris Johnson’s unrivalled public popularity should a leadership contest arise in six weeks’ time it is hard to imagine him not being a clear favourite.

Labour presents an equally interesting, though apparently not so obvious proposition in Shadow Business Secretary Chuck Umunna, first elected to parliament in 2010.

Fast rising up the party ranks, a formidable media performer and someone with the potential of winning over the business community that Miliband couldn’t, don’t be surprised to see a reinvigorated Opposition led by him or Johnson in five years’ time.