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Brexit is now unstoppable. But Britain must face up to how long it will take

London(CNN) Boris Johnson campaigned on a single, simple slogan: "Get Brexit done." Britain, it seems, could not have agreed more.

Fed up with the political turmoil over Brexit at Westminster, voters gave Johnson the mandate he craved to get the country out of the European Union by January -- no ifs, no buts.

They may be disappointed. Far from Brexit being done, it's just getting started.

In reality, Johnson's Brexit "deal" is just the first stage in a years-long process. Not that you'd have heard much of that from the Prime Minister, who preferred his catchy slogan to any complicated discussion about the framework of a future relationship with the EU or the long-term implications of quitting the bloc.

Johnson just doesn't do nuance. In a political stunt on one of the final days of stumping, he drove a "Brexit" backhoe through a wall of polystyrene bricks emblazoned with the word "gridlock." But he successfully ducked difficult questions about what delivering Brexit might look like in reality, limiting media appearances and even retreating into a walk-in refrigerator to avoid a TV interview.

Live: Full UK election results

The Conservative Party's campaign manifesto was similarly light on detail, avoiding any real insight into how Johnson plans to negotiate a trade agreement with Europe in just 11 months -- a process that typically takes years.

That strategy seems to have worked, and Johnson's so-called "oven-ready" deal is now expected to pass through Parliament in the coming weeks, ushering Britain out of the EU by the end of January.

It's the type of decisive mandate that Johnson's predecessor Theresa May hoped she might secure when she called a snap election in 2017; instead, opposition leader Jeremy Corbyn stunned the political establishment by engineering a Labour Party surge that cost May her parliamentary majority, forcing her into an awkward arrangement with a hardline party from Northern Ireland that limited her room for maneuver.

Boris Johnson drives "Get Brexit Done" backhoe in campaign stunt.

Corbyn failed to generate the same enthusiasm this time around. His campaign was plagued by relentless in-fighting and allegations of anti-Semitism. But it was his neutrality on the single biggest issue facing the country that seems to have led to his downfall. Corbyn had campaigned on a wishy-washy Brexit policy, promising a confirmatory second referendum on a softer Brexit deal, but refusing to say which side he would back.

"Labour will be seen as having allowed Brexit," says Professor Tony Travers, director of the Institute of Public Affairs at the London School of Economics. "One of the terrible ironies in all of this is that Boris Johnson probably broadly didn't want to leave the EU, but now is in a position whereby he has to make it happen. Corbyn, on the other hand, who did want to leave, has tried -- and failed -- to articulate a possible remain position for his party."

As a result, the Conservatives managed to flip areas long held by Labour -- working-class party heartlands that wouldn't have dreamed of voting for the Conservatives even 10 years ago -- which had backed Leave in 2016.

In one fell swoop, Labour has effectively been relegated to the sidelines -- along with its radical, socialist policy plans -- delivering the Conservatives a majority that has not been seen since the era of Margaret Thatcher.

Now the question is, what is Johnson going to do with his new-found political power?

It's important to remember that a lot of the challenges for the UK have yet to come. After the Brexit deal is passed and ratified in January, the UK moves into an even more expansive and complicated negotiation period, setting out just how closely aligned it will stay to the EU on issues like the environment, competition, workers' rights and trade.

Johnson is hoping to secure a new trade agreement with the EU by the end of 2020, before the end of the so-called transition period -- during which the UK will be formally out of the bloc, but still subject to all its rules and regulations. That's a quick turnaround, especially if he seeks to diverge significantly from EU rules, as he has indicated. And, given Johnson's emphasis on sticking to the December 2020 deadline, it is likely that he will have to compromise on just how deep and ambitious any deal might be.

BBC exit poll shows Johnson's Conservative Party winning the election.

"The main constraints on Boris Johnson will no longer be the House of Commons, but time," says Brigid Fowler, a senior researcher at the Hansard Society, indicating that his ambitions for a "fantastic new free trade agreement" may be constrained by the ever-ticking clock. "If you're up against that tight of a timetable, it would seem to militate against any sort of bespoke arrangements for the UK and indicates more of an off-the-shelf solution."

Still, such a large parliamentary majority affords Johnson a lot of freedom in shaping that deal, at least from the UK side.

"It opens up Boris Johnson's leeway and ability to move in the next phase, but doesn't mean the situation for the EU significantly changes," says Joe Owen, Brexit program director at the Institute for Government think tank.

In the early hours of Friday morning, European Council President Charles Michel said the EU was "ready to negotiate" whatever the outcome of the election.

And the second phase of Brexit negotiations is set to be more trying than the last. For months we have watched Westminster for make or break votes, but the ratification process will turn our collective attention to parliaments all across the European Union -- every member state will get a vote and veto on the framework of the UK's future relationship.

Further still down the line is implementation. Negotiating and ratifying a deal is one thing, but actually putting it in place and transferring it into the systems of government is another. It's a process that has the potential to drag on for years.

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