LONDON (Reuters) - Britain is expected to hold an election next month that will determine the outcome of its three-year Brexit crisis, with each of the major parties taking a different stance toward how, when and whether the country should leave the European Union.

Police officers walk past pro-Brexit banners outside the Houses of Parliament in London, Britain October 29, 2019. REUTERS/Henry Nicholls

What are the positions of the main parties?

BORIS JOHNSON’S CONSERVATIVE PARTY - EXIT WITH A DEAL

Johnson has pledged to campaign in favour of Brexit. He wants to implement the exit agreement he agreed with the EU earlier this month as soon as possible, before going on to negotiate a long-term, free-trade agreement with the bloc next year.

The Conservatives won 318 out of 650 seats at the 2017 election. This made them the largest party, but to be certain of a majority in parliament they had to make a deal with Northern Ireland’s Democratic Unionist Party, which won 10 seats.

The Conservatives are ahead in opinion polls, but polling is volatile and the election is expected to be hard to predict. In 2017, the party had a large lead in the polls but ended up losing seats overall.

JEREMY CORBYN’S LABOUR PARTY - SECOND REFERENDUM

Corbyn wants to go back to Brussels and negotiate a different Brexit deal. He wants greater protections for workers’ rights and the environment, and thinks the country’s long-term relationship with the EU should be a customs union.

Labour would then put this new deal to the public in a referendum which offered the choice between the Labour Brexit deal and remaining in the EU.

The party has not decided which option it would back in this referendum.

Labour won 262 seats in 2017, making them the second largest party. The party currently trails the Conservatives in opinion polls published in October, but estimates of the gap vary between 16 percentage points and 3 percentage points.

JO SWINSON’S LIBERAL DEMOCRAT PARTY - CANCEL BREXIT

The Liberal Democrats want to stop Brexit altogether. If the party won a majority, it would revoke the ‘Article 50’ notice which informed the EU that Britain wished to leave, effectively cancelling Brexit.

The Liberal Democrats won 12 seats in 2017, but defection from other parties have increased the number of votes they have to 19. Polls currently put the party in third place behind Labour and the Conservatives.

In 2010, the Liberal Democrats won 57 seats and formed a coalition government with the Conservatives.

NICOLA STURGEON’S SCOTTISH NATIONAL PARTY - ANTI-BREXIT

The SNP is anti-Brexit and wants to see Scotland become an independent country inside the EU. They are staunchly opposed to a no-deal Brexit and would support a second referendum on whether to leave the EU. The party opposes Johnson’s Brexit deal.

The SNP contest the 59 British parliamentary seats which are based in Scotland. At the last election it won 35 of them, and so constitutes a large bloc of votes in parliament.

NIGEL FARAGE’S BREXIT PARTY - CLEAN BREAK BREXIT

The Brexit Party argues for a “Clean Break Brexit” and opposes Johnson’s exit deal. The party is less than a year old and is led by one of the country’s most recognisable Brexiteers, Nigel Farage.

The party has never competed at a national parliamentary election, but took part in European Parliament elections in May and won the largest share of the vote at the expense of Labour and the Conservatives.