Just in, reaction from the prime minister to Nigel Farage's announcement....

Speaking on the campaign trail, Boris Johnson says: "I'm glad that there is a recognition that there is only one way to get Brexit done and that's to vote for us and to vote for the Conservatives."

Asked whether he called Mr Farage ahead of the move, the PM replies: "Absolutely not!"

As for whether the Conservatives' chances have been boosted, Mr Johnson says the party is "working hard for every vote" and "only needs nine more seats" to get a working majority in the House of Commons.

BBC political editor Laura Kuenssberg points out Sir Keir Starmer, shadow Brexit secretary, giving the sort of the reaction we're likely to see from a lot of Labour figures - using Nigel Farage's decision against Boris Johnson.

Peter Barnes
BBC political analyst

The Brexit Party’s decision to stand aside in constituencies the Conservatives won in 2017 should make it easier for them to hold on to those seats.

In marginals like St Ives and Mansfield, it ought to help them keep a bigger share of the pro-Leave vote.

However, to win a majority in the House of Commons, the Conservatives need to win more seats - not just hold onto what they have.

And in those places the presence of a Brexit Party candidate may get in the Conservatives’ way.

The best estimates suggest that 29 of the Conservatives top 50 targets, and 59 of the top 100, are in Labour-held seats that voted Leave in the referendum.

If the strategy is to target Leave voters in those places, it would probably better to have a clear run - without The Brexit Party.

Image source, Reuters

The morning started off quietly but ended with a significant moment - although we won't know just how significant until the early hours of 13 December when the results are being counted.

So what's happened?

• The Brexit Party are to stand down their candidates in the 317 seats won by the Conservatives at the last election, meaning they will not contest any of them
• But Nigel Farage indicates his party will fight all the other seats in Britain, held by Labour and pro-Remain parties such as the Lib Dems, SNP and Plaid Cymru
• He said it had not been an easy decision but he was putting "country before party" by reducing the chances of a hung Parliament and another EU referendum
• He said his change of mind was prompted by Boris Johnson in recent days promising a looser economic relationship with the EU after Brexit
• The Conservatives have welcomed the move but the Lib Dems said there was now no difference between the Tories and the Brexit Party
• Elsewhere, we've had pledges on the armed forces and on adult education, and the latest GDP figures for the UK

BBC Politics Live
BBC2's lunchtime political programme

And now for the Conservatives' first reaction. Party chairman James Cleverly says: "I welcome the recognition that The Brexit Party do risk actually preventing a stable majority government and I welcome the fact that that's been taken on board."

Speaking to Politics Live on BBC2, he says there is still a "danger" that in seats where The Brexit Party is running - Conservative targets - they might still split the vote, leading to an MP winning the seat who's "going to frustrate the Brexit process".

Politics Live's Jo Coburn asks Mr Cleverly repeatedly whether there'd been any discussions between the Conservatives and The Brexit Party about withdrawing candidates, but he insisted there hadn't.

Another panellist, the political commentator Iain Dale, remarks that while Mr Cleverly looks "calm" he must actually be "euphoric", adding that, in his view, this is "one of those big election moments".

What does Labour think of the news that Nigel Farage says he wants to "take the fight to Labour" rather than the Tories at the election?

Well, this is the official reaction...

And below, the feelings of the shadow education secretary.

Lib Dem leader Jo Swinson has reacted to Nigel Farage's announcement by saying there is now no difference between The Brexit Party and the Conservatives.

We are likely to hear a lot more of that from pro-Remain politicians.

A reminder that Mr Farage had previously pledged to field more than 600 election candidates, but told a press conference a short time ago he now believed that doing os would result in a hung Parliament and put Brexit in jeopardy.

BBC News Channel

Away from Nigel Farage's announcement, the SNP's business spokesperson, Drew Hendry, is appalled at figures out today, showing that the economy has grown at its lowest rate in almost 10 years.

Mr Hendry calls it a "dreadful situation", saying the government had "scraped by only because of Brexit preparations" with businesses investing a lot of money in stockpiling.

And GDP doesn't tell the whole story, he says, because "people don't care about percentages, they just see widening inequalities."

Rather than focusing on "pure raw wealth", the focus should be on how "happy" communities could be, he adds.

The BBC's political correspondent Alex Forsyth says The Brexit Party could still have a huge impact on the election by standing candidates in marginal Labour seats in Leave-voting areas that the Tories need to take to win a majority.

She says there is a chance The Brexit Party will still "split the vote" among Brexit supporters, who may be conflicted over whether to support Nigel Farage or Boris Johnson.

So, she adds, while there may be "some relief" within the Conservatives at Monday's announcement, it is not the end of the story as far as the election result is concerned.

Nigel Farage says he has "no great love" for the Conservatives, but giving Boris Johnson "half a chance" in the election will stop another Brexit referendum.

He says the way to "keep Boris Johnson to his promises" is to get MPs elected to Parliament in the remaining seats it is fighting.

"In a sense we now have a Leave alliance, but we have done it unilaterally. We have decided we have to put country before party and take the fight to Labour."

Nigel Farage says the Brexit Party will not contest the 317 seats won by the Conservatives at the last election.

However, the party will fight all the other seats held by Labour and other "pro-Remain" parties.

This is a huge moment in the campaign and the announcement is met with big applause from Brexit Party activists.

Nigel Farage says he has been encouraged by Boris Johnson's commitment not to extend the transition period beyond the end of 2020 and to negotiate an enhanced free trade agreement based on the EU's agreement with Canada.

He says this is a "huge change" and sounds more like the Brexit that he and others voted for. Not being in political alignment with the EU is a big step in the right direction.

Here it comes, that "but"... Nigel Farage says he has to weigh up his dislike of Boris Johnson's deal with the impact on the campaign and result of the Brexit Party fighting the election.

He says it's "not been easy" but he fears that if his party fields 500 candidates, as he previously said it would, it could lead to the Lib Dems winning seats and a hung Parliament. This, in turn, could lead to another referendum.

He says he has genuinely tried to build a leave alliance but this has "come to nought".

Nigel Farage begins by saying he sympathises about those worried about "Brex-exhaustion".

But he says, unlike many others, he actually read Boris Johnson's new Brexit deal and there were many things he did not like it.

Two things were "completely unacceptable" - the main one being the PM's claim that it would get Brexit done when that was clearly not the case.

In fact, he said the proposed agreement would give the EU the "upper hand" in negotiations over a future trade deal.

He also says the UK would not have sufficient freedom to diverge from the EU in tax and other regulatory matters.

However, there's a sense that there's a big "but" coming in this speech...

Nigel Farage is now speaking in Hartlepool.

This is the third major event of the Brexit Party's campaign.

At the first, Mr Farage gave Boris Johnson an ultimatum to ditch his deal by 14 November or face The Brexit Party standing more than 500 candidates across Britain.

Why 14 November? Well, that's the deadline for parties to nominate and register their candidates. We are three days away from that so expect some clarity soon...

Ready for the arrival of Nigel Farage. There are whispers of something significant potentially being announced... we'll keep you posted!

Chancellor Sajid Javid says the best way to end uncertainty over Brexit - and any drag it is having on the economy - is to elect a Tory government that will be able to get Boris Johnson's "great deal" through Parliament within weeks of the election.

During a visit to a housing development to mark the latest GDP figures, he says there have been nine consecutive years of economic growth under the Conservatives and record levels of employment.

He also says he would be prepared to take on his opposite number John McDonnell in an election debate.

A reminder that Britain's economy has grown at the slowest annual rate in almost a decade, although recession has been avoided.

Baroness Warsi, the former chair of the Conservative Party, has been fighting a running battle with the party over the issue of Islamophobia.

She has accused Boris Johnson of downgrading an inquiry into the extent of the problem, having previously suggested Theresa May had "buried her head in the sand" over it.

She's been speaking to Emma Barnett on BBC Radio 5Live this morning about the issue. Here's a flavour of the interview.