British lawmakers meet on Saturday to debate and vote on the Brexit deal negotiated by Prime Minister Boris Johnson with the European Union. It is the House of Commons' first Saturday session since the Falklands (Malvinas) War of 1982.

If members of parliament vote for the deal, the UK will officially, finally, leave the EU on 31 October. If they vote against it, there will probably be a further delay to Brexit to 31 January, although if the EU rejects that idea, there could be a no-deal Brexit in 12 days.

The winning post for a vote is 320 and this one is seen as too close to call. So how do the numbers stack up for the deal?

Conservative Party
Most of the 288 Conservative MPs in parliament are expected to back Johnson, however a few on the purest-Brexit side of the party may oppose the deal because of concerns over the impact on Northern Ireland.

Conservative rebels
A group of 21 MPs were kicked out of the parliamentary Conservative Party for opposing the government's plan to risk a no-deal departure if necessary. Many, but not all of these, would be expected to back the new deal.

Democratic Unionist Party
The DUP says its 10 MPs will oppose the plan because of what it sees as its impact on Northern Ireland's place in the UK. To have a good chance of success Johnson may have to change their minds.

Labour Party
Labour's leadership oppose the deal, saying they could secure a better one. However, several of the party's 245 MPs from areas that voted to leave the bloc may back the deal. But they know siding with Johnson could be toxic for them in the future. The numbers that decide to abstain, or to back the deal, will be crucial.

Scottish National Party
The Scottish National Party wants to stay in the EU and have voted against all forms of Brexit. Its 35 MPs are expected to all oppose the deal.

Liberal Democrats
The Liberal Democrats want to stay in the EU. Eighteen of their MPs are almost certain to reject the deal, with just Norman Lamb still undeclared.

Independents, Green Party, Plaid Cymru
The smaller parties and the independents in the House of Commons are all opposed to the deal.