British Prime Minister Theresa May shocked the nation when she announced on Tuesday that a general election would be held on 8 June, not least because May herself repeatedly made it plain that Britain wouldn't have an election before 2020, when the fixed term of the parliament elected in 2015 would expire.
No UK election has come so out of the blue since February 1974, when Edward Heath, goaded by striking miners, went to the country in an attempt to confirm his authority. He lost, an outcome that for more than 40 years has deterred other British leaders from trying a similar tactic when issued with a challenge from the polity.
In explaining her change of mind, May stated that she needed a new mandate to enable her to deal authoritatively in the negotiations about Britain's departure from the European Union. A small number of MPs in her own party (and most of those outside it) were trying not so much to derail the decision of last year's referendum to leave the EU as to moderate its effects. May knew that such a dilution of these effects (such as agreeing not to impose border controls on some EU nationals) would be contrary to the wishes of a majority of Britons, and could not be tolerated. Her only option, therefore, was to try to reduce the size of the opposition she was facing.
This election is likely to achieve that aim, and is why May is unlikely to replicate Heath's experience. The last opinion poll published before the announcement gave the Conservative party a 21-point lead. The approval ratings of Labour leader Jeremy Corbyn are so low as to be subterranean. Polling day is seven weeks away, but it is hard to imagine the catastrophe that would prevent May from getting her mandate, and getting it with a majority substantially larger than she has today.
Word from the EU since the election was called is that it would feel happier to negotiate with a newly-mandated British leader. For Brexiteers in May's party, they believe a victory will (as she claimed in calling the election) finally silence those in the Liberal Democrats, Greens and Scottish National Party who are looking for some way of derailing the desire of the British people to leave the EU. The Labour Party has made very little effort to counter the democratic decision of last June, not least because the hard-left MPs who currently run the party have a long history of disliking Europe.
If the Conservatives are returned with a large majority, EU negotiators will know there is a limit to how far they can push Britain on matters such as the European single market and freedom of movement. Until the election was called, there was a sense that divisions among parliamentarians might enable the EU to be unyielding in any deal offered to Britain. If it knows the UK government has strong public support, the most likely victim of any hardline policy would be the EU itself.
The unexpected election does not merely come at a crucial time for Britain's EU negotiations, it also comes at a highly unstable time for international relations. Britain can be little more than a spectator in the rhetorical jousting between North Korea and the US, but it is aware of China's interest in the question, and keen to develop its relationship with Beijing as a post-Brexit trading partner. For the same reason, May has already established good relations with US President Donald Trump (remaining good friends with both powers may prove diplomatically challenging).
On Syria (and Russian support for Bashar al-Assad), the other international difficulty of the moment, Britain is and will remain solidly supportive of the US. British relations with Russia have been bad ever since the Kremlin-sanctioned murder of Alexander Litvinenko in London a decade ago, and can't get any worse short of an outright declaration of hostilities.
Assuming May is returned, the election will give her the opportunity to review not just policy affecting international relations and security, but also personnel. There may be no alliances to review, but many Tory voters are disturbed by the inadequacy of the nation's defences, and want more spent on arms and recruiting members of the military. There also remains some disquiet about the calibre of Foreign Secretary Boris Johnson, who is not felt to have distinguished himself in the aftermath of the Syrian chemical weapons attack. He will need to make a positive impact during the coming campaign, as any more indicators that he is out of his depth could result in assignment to another cabinet post.