If Gordon Brown wants Labour to remain in Government he should call the next General Election for October or February, according to the academic behind a pioneering historical website which came online this week.

The site – www.visionofbritain.org.uk – draws on and connects over 12 million historical facts, maps, observations and images to show how life has changed in some 15,000 British towns and villages over the past 250+ years.

Much of the information has never been published online before, including 70 years of unemployment and wage records, farm surveys from 1866, an influential land use survey, writings by agitators and social reformers and the results of every Parliamentary election, nationally and by constituency, since 1833.

The site is designed for general users but it is the first e-publication of 175 years of election data which is most likely to interest today’s politicians and pundits, says project director, Dr Humphrey Southall of the Great Britain Historical GIS.

“For students of history, the election results give fascinating insight into the rise and fall of political parties; how certain issues become mainstream or fade, and the growth of the political contest. But Westminster watchers may be more interested in the pointers they give to the best time to stage an election if a party wants to keep or regain power.

For instance, going by past outcomes, Gordon Brown should avoid May as that is the month that has produced the most Opposition wins, while David Cameron and Nick Clegg should look dimly on October or February as, historically, they rarely see the Government change.”

Other political trends thrown up by the data show that:

* Despite big increases in the number of people casting votes (up from 735,527 in 1833 to over 27m at the last General Election), the share of votes awarded to the Conservative Party's share has remained fairly constant, hovering at around the 45% mark for 175 years.

* It has been more than 50 years since a sitting candidate was returned to Parliament unopposed, or any seat went uncontested, and nearly 75 years since the number of uncontested seats reached double figures. By contrast, the General Election of 1857 gave an automatic shoe-in to 283 MPs (51.45%).

* Statistically, over the long-term, a Government has about the same chance of staying in power following a General Election as it does of losing; in the 44 held since 1833, 23 have resulted in no change of power.

The creation of the site’s elections files, and many other additions and improvements, have been made possible by funding from the Joint Information Systems Committee (JISC) as part of an initiative to give a wider audience free access to academic materials.

Humphrey Southall explains: “It’s a safe bet to say that with the creation of www.visionofbritain.org.uk, we are unlocking a portal to the web’s biggest collection of historic materials about places and lives in Britain, spanning many centuries and themes. The range and depth of the information makes it a terrific resource for professional and amateur historians but the site isn’t just a way to look back. The content is already in demand from researchers and forecasters watching for changes and trends of relevance now or in future.”