Boris Johnson has just days to secure a new Brexit deal with the EU summit starting on Thursday in Brussels.

Talks between the bloc and the UK are on a knife-edge with hopes and fears being routinely dashed in the run-up to the crunch talks.

Here the PA news agency looks at some of the key players involved in negotiations:

– Boris Johnson

It should go without saying but it bears repeating that any final deal needs to be palatable to the man who will have to reap or bear the political repercussions.

Boris Johnson promised throughout the Conservative Party leadership contest a more gung-ho approach to the negotiations and that has been borne out through clashes in the Commons over his language and whether he will obey the Benn Act, a law that looks to extend the Brexit deadline.

The Prime Minister currently looks to be totting up the numbers to determine whether, if there is a eureka moment coming in Brussels, he has the support to get a deal through the Commons.

– Stephen Barclay

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Brexit Secretary Stephen Barclay (Jeff Overs/BBC)

The Brexit Secretary. Seen as a middle-of-the-road Leaver, he replaced Dominic Raab in the role when he resigned from Theresa May’s cabinet over the terms of her Withdrawal Agreement.

But Mr Barclay was kept in the post by Mr Johnson during his drastic reshuffle after taking the reins of the Tory party and was given a more beefed up role in terms of the negotiations.

He has held regular meetings with key players across the continent, sounding them out for any way to a deal. Mr Barclay maintained on Tuesday that “a deal is still very possible”.

– Michel Barnier

Heralded for the way he has kept the other EU27 members united around a Brexit position, the EU’s chief negotiator has been involved at every step of the way since being appointed by the European Commission to lead the Brexit talks.

The 68-year-old’s office is one of the first stop-offs for UK MPs when they visit Brussels to discuss the divorce terms progress.

The Frenchman has called on the Prime Minister to produce a legal text if he is to secure a deal at this week’s European Council.

– Leo Varadkar

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Taoiseach Leo Varadkar (Niall Carson/PA)

Since taking the reins in Dublin in May 2017, the Irish prime minister has become a major character in the Brexit saga and unequivocal about the need to avoid a hard border in Ireland.

Seen as one of the main power brokers in the talks, Mr Varadkar is being looked to by the EU27 to judge whether the Downing Street proposals for Northern Ireland after Brexit are passable.

Mr Johnson’s initial “two borders” pitch for a deal – that wanted to take Northern Ireland out of the EU customs union, in a move that would have meant checks at vicinities around the Republic of Ireland and in the six counties – was given short shrift by Mr Varadkar.

But it was a meeting between the pair of leaders at a luxury hotel on the Wirral last week that gave Brexit addicts one of their most memorable moments.

Following a walk through the wedding venue grounds, they agreed there was a “pathway” to a deal, setting into motion a new urgency on both sides of the Channel to secure an agreement.

– David Frost

The so-called Brexit sherpa, he is Mr Johnson’s most trusted aides when it comes to delivering his Brexit message and working out how Britain can leave by October 31.

He replaced Theresa May’s Brexit man Olly Robbins, who was often portrayed as a villain by Eurosceptics for his handling of the talks.

A man who, in all likelihood, knows the Eurostar check-in regime better than the back of his hand, he has spent more nights in Brussels hotels than in his own home in recent weeks.

A former special adviser to the PM when he was foreign secretary, he was locked in fierce talks during the weekend, along with his 20-strong team, after last week’s breakthrough meeting with Irish prime minister Leo Varadkar.

When it comes to the latest Brexit developments, he is the man in the know.

– Arlene Foster

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DUP leader Arlene Foster (David Young/PA)

Unlike during Mrs May’s reign, Mrs Foster’s DUP party could be interpreted as having a less crucial role because it no longer props up a fragile majority after Mr Johnson lost his Commons advantage.

But Ms Foster and Nigel Dodds, her deputy and Westminster leader, are still seen as key in Downing Street and have been granted audiences with the PM at Number 10 twice in as many days.

The reality is Mr Johnson would need the backing of every MP he could get to shepherd any deal through the Commons, and the DUP wield influence over the European Research Group (ERG) of hardline Tory Brexiteers.

Mrs Foster’s outfit has been approving recently, it remains to be seen how Mr Johnson will accommodate the EU’s demands for no checks on the border and ensuring the integrity of the single market, while also placating the DUP’s demands not to have checks in the Irish sea on goods travelling between NI and Great Britain.

– Angela Merkel

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German Chancellor Angela Merkel and Prime Minister Boris Johnson in Berlin (Stefan Rousseau/PA)

The German Chancellor may face political instability at home, but in Brussels, her opinion is said to still be the one that matters most.

In the summer, Brexit hit the headlines again after she outlined a 30-day window for Mr Johnson to put his proposals before leaders in a bid to put some rigour into the talks.

Mrs May was seen to cosy up to Ms Merkel when looking to push a deal through and Mr Johnson will have to make similar overtures if he wants to travel back to London on Friday with all 28 signatures on a Withdrawal Agreement.

– Emmanuel Macron

The French president was the second EU leader Mr Johnson chose to visit in the summer, following his trip to Berlin, and he is a respected voice in the council.

Mr Macron has taken a tougher line on whether Britain should be granted any further extensions but, with his domestic polling taking a dip, some commentators see his approach to Brexit as playing to French voters.

The PM spent “20 minutes or so” on the phone to his counterpart in Paris on Tuesday – proof of his influence and the need to have him on side before leaders convene in Brussels.

– Jean-Claude Juncker

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Prime Minister Boris Johnson with European Commission President Jean-Claude Juncker (Stefan Rousseau/PA)

It speaks volumes about the importance of Mr Juncker’s role as president of the European Commission that some Brussels-based media were more interested in the election of his successor than the Brexit process this autumn.

Boss to Mr Barnier, the outgoing leader is one of those Mr Johnson will have to satisfy in order to get a deal. The pair lunched together last month, enjoying courses of snails and salmon, so they are no strangers.

Mr Juncker has made it clear he would approve an extension to the Brexit negotiations if the UK requested one.

– Donald Tusk

The European Council president is in charge of putting together the agenda for when the leaders of the 28 member countries meet four times a year.

The former Polish prime minister is the go-between when it comes to liaising with European leaders.

He has previously accused the former mayor of London of playing a “stupid blame game” when it comes to pitting the EU against Britain.

It awaits to be seen whether he deems that sufficient progress has been made on doing a deal to put it on the agenda for Thursday and Friday’s summit in Brussels.

There is also talk of having to approach Mr Tusk about organising an emergency summit for later in the month if the I’s and T’s are not dotted and crossed yet on the Withdrawal Agreement.

– Tim Barrow

A well-travelled diplomat, Mr Barrow took over as permanent representative of the UK to the EU following Sir Ivan Rodgers resignation in January 2017.

He represents the soft arm of the negotiations, feeding information back to Downing Street on his discussions with EU officials and other diplomats from member states in between the crunch points.

Mr Barrow was the official who handed over Mrs May’s letter triggering Article 50 and he will be by the PM’s side while in Brussels for the European Council summit.

– Guy Verhofstadt

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Guy Verhofstadt pictured at the Liberal Democrats conference (Jonathan Brady/PA)

Another EU power player, the Belgian MEP is the Brexit co-ordinator for the European Parliament.

Deeply committed to the European project and the only one out of Mr Tusk and Mr Juncker to be elected by the people, he has taken a firm public – and sometimes controversial – view on Britain’s decision to leave the EU.

He attended the Liberal Democrats conference in September where he proudly showed off their “B*llocks to Brexit” t-shirt slogan and called Mr Johnson the “real traitor” in reply to briefings that Remain-backing MPs were “colluding” with the EU.

Seen as a big player in the parliament, his influence is not on the same level as the aforementioned commission and council presidents.

– Steve Baker

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Steve Baker MP (Dominic Lipinski/PA)

The leader of that crew of hardline Tory Brexiteers, he has indicated he could back a deal secured by the PM if the DUP is in support of it.

Mr Johnson has also been keeping him close and will be buoyed by Mr Baker’s use of the description “constructive” to paint a picture of discussions between his group and No 10.

It was Mrs May’s failure to get the ERG on board for her deal that ultimately helped cost her the top job.

Briefing reporters outside Downing Street on his meeting with the PM on Tuesday, Mr Baker said: “It was a very constructive conversation, and I am optimistic that it is possible for us to reach a tolerable deal that I will be able to vote for.”