What's that, you say? The 2015 UK election hasn't happened yet? Well, it's happening soon, May to be exact, and thankfully for us there is a website called Electoral Calculus which posts projections for all the seats. So let's get going.
The Landscape:
The UK, like most other Anglo countries (and unlike the rest of the Western world), elects its legislature through the first-past-the-post system. For those unfamiliar with political science terms, that simply means every legislator represents a district, and whoever gets the most votes in that district gets elected, even if they don't obtain a majority. In the US, that's usually not a problem, because it's very rare to win under 50% of the vote, and winning under 45% is almost unheard of (in primaries, that's another story). That's how, in 2010, the Conservative Party received 36% of the vote and won 47% of the seats, with the Labour Party obtaining 29% of the vote and 40% of the seats. If you're astute, you'll notice that neither 47 nor 40 is greater than 50, the percentage of seats required for legislative control. In came the Liberal Democratic Party, which unfortunately for them received 23% of the vote but only 9% of the seats. However, 47 + 9 = 56, and thus the Tories (Conservative Party's nickname) earned themselves a coalition government with the LibDems for the next five years.
PM David Cameron's government has pushed through a few pieces of serious legislation. Major reforms enacted include some cuts to welfare housing allowances, an education reform that I frankly don't understand but would love a British commenter to explain to me, a very controversial health care law, an immigration crackdown law, and the legalization of same-sex marriages. However, all this has been done in the shadow of the global financial crisis, which has lasted longer in Europe than in America. The Cameron government pushed austerity measures, which many including myself argue helped prolong the recession. The UK economy seems to be recovering some, with GDP growing 2.3% in 2013 and 2.6% in 2014 after a disastrous 0.4% growth rate in 2012, but Cameron has certainly been hurt by the economy.
While Cameron has weathered his term in mediocre (but definitely not good) shape, Deputy Prime Minister Nick Clegg, leader of the Liberal Democrats, has been an unparalleled disaster. Much of this isn't his fault; any party which normally serves as a protest vote but then joins the government will lose half their support, but Clegg was also hurt by a quick flip-flop on his promise not to raise student fees which helped him earn a disproportionately high percentage of the youth vote in 2010.
Labour, on the other hand, is led by the hapless Ed Milliband, sort of a left-wing version of Mitt Romney. They both share the same awkwardness around average Americans, and both are frequently attacked for being out of touch and elitist (as is Cameron, to be fair). Milliband has presided over a party that polled at 42% in 2012 and is now polling at 33%, while the Tories have essentially stayed stable.
Remember that in the rest of the world, red=left and blue=right. The LibDems are yellow.
What's that purple, you ask? Why, that's the UK Independence Party. If the Tories are the Chamber of Commerce Republicans, the LibDems are the New Democrats, and Labour are the Progressive Caucus (all of which I think are fairly accurate), the UKIP is Britain's Tea Party. They have surged from being a non-factor in elections to polling at 15% of the vote by running against the European Union and attacking the major parties on immigration. Due to first past the post, they will likely obtain 5 seats at most out of 650, but they are a factor by drawing votes away from the Tories and increasingly Labour as well. The Green Party is also increasing, mainly as a protest vehicle for left-wing voters who dislike Milliband or centrist voters who just want to vote for a party which is neither Labour nor in government.
Electoral Geography:
Britain is, like the United States, geographically polarized. Also like the United States, Labour tends to do well in cities, with the Tories doing well in rural areas. However, one major difference is the suburbs, where the Tories run up dominant margins in the types of areas that have abandoned the Republican Party during the 1990s and 2000s, the British equivalents of the Upper East Side or Lake County, Illinois. The color code here is extremely complicated, owing to the number of parties involved. Keep these simple things in mind.
Red=Safe Labour seats
Blue=Safe Tory seats
Black=Safe Nationalist seats (we'll get to those, I promise!)
Purple=Pure Tossups between Tories and Labour
Green=LibDems
Other combinations you don't see=projected close races between two parties, one of which is a minor party
[I got all my data from electoralcalculus.co.uk, so blame them if this is all wrong]
Generally, the Tories do extremely well in the South of England outside of London. Labour holds only a handful of seats in this half of the country, and only about a dozen more are expected to be close. The LibDems won 23 seats (scattered, but many in the southwest of the country) in this region in 2010; many will flip back to the Tories, while a handful will be held and a couple will go to Labour. Labour tends to be competitive only in larger towns and small cities like Exeter, Plymouth, Bristol, and Southampton. In 2010, Labour won only 10 seats in the South outside of London; in 2015 they will need at least twice that many.
London's suburbs are almost uniformly Conservative, as cultural issues matter less in British elections and thus there is no reason for these wealthy, business-oriented voters to choose Labour. There are about five competitive seats for Labour out of the entire suburban region.
London itself votes significantly for Labour, but there are large areas which vote for the Tories, and a few LibDem seats, too. Labour should hope to pick up 6 seats in London; 8 gains are plausible, and the Tories will gain a couple more from the LibDems, too.
The Midlands are home to the major city of Birmingham, the smaller cities of Leicester and Nottingham, rural areas, and former small-town manufacturing hubs. In many ways, everything in the northern half of the country mirrors the Midwest of the United States. It's pretty heavily White (almost everywhere is outside of a few large cities) and it has a strong organized labor history due to its manufacturing. The further north one goes within England, the better it generally is for Labour, and as you can see from the map they will win over 20 seats in Birmingham alone and should take another dozen in the Nottingham/Leicester area. There are also a decent number of scattered "marginals" (the British term for swingy seats) scattered around between the deep blue ones.
Wales is a Labour stronghold, and the party should gain nearly every seat there, with a handful split between the Tories, Welsh nationalists, and possibly even a LibDem seat or two.
Manchester, Lancashire, and Yorkshire (the North) are Labour's base. Historically centered around mining and manufacturing, one could think of the area as the equivalent to Western Pennsylvania and Eastern Ohio. Labour's hold on them is slipping a bit, but not as much as the Democrats' here. Liverpool, Manchester, Leeds, and Sheffield and their surrounding areas (the inset) contribute about 60 seats or more to Labour while only giving the Tories a single-digit number. Head up even further north and there are a few more Tories, but there are also twenty more Labour seats in the coastal areas.
Scotland has been the most interesting part of the country in the past year. About 45% of their voters opted to support independence, and now nearly all those voters are supporting the Scottish National Party instead of the traditional Scottish party of choice, Labour. This is likely what will cost Labour their majority, as Scotland was formerly Labour's best region, with some LibDem support there too. Now, Labour will have to make up at least 30 seats in other parts of the country, a difficult task given polling. Within Scotland, Glasgow has retained much more support for Labour (about a 50-50 split in seats with the SNP) as compared to Edinburgh and the North of Scotland, where every seat will likely go SNP except the Shetland/Orkney seat which always votes for the LibDems.
Northern Ireland has completely different political parties, so I'm ignoring them. No offense to any of you Northern Irelanders out there.
So where does that leave us? Well, ElectoralCalculus says there is a 58% chance of a certain Labour government (split about evenly between a Labour majority and a coalition) and a 29% chance of a certain Tory government, also split about 50-50. The remaining scenario is that the SNP gets to choose which party it wants to give the majority too. One would expect them to choose Labour based on ideological similarity, so I'd say there is in reality about a 2/3 chance of PM Ed Milliband come this summer and a 1/3 chance of PM David Cameron. This also means there is a 57% chance of something unprecedented in modern British politics: back-to-back coalition governments. It'll be a fascinating ride, that's for sure.