In the next half hour or so, we're expecting to hear from both Boris Johnson and Jeremy Corbyn.

The prime minister will speak at a rally in Colchester, a Tory-held seat in northern Essex which the party would normally be confident of holding.

The Labour leader is in Hastings, a key target for the party. It missed out on the Sussex seaside seat by just over 300 votes at the last election.

The opinion polls keep coming thick and fast.

What can we read into the latest ups and down and what, if anything, do they indicate about the likely result on 13 December?

Sir John Curtice, the psephologist's psephologist and professor of politics at Strathclyde University has been speaking to Adam Fleming on the BBC's Electioncast.

Donald Trump and other world leaders are flying into the UK on Tuesday for a gathering to mark the 70th anniversary of Nato.

The event comes at a time when some are questioning the relevance of the defence and military alliance.

Labour candidate Dan Jarvis has written an article for Labour List, urging the next prime minister - whether it is Boris Johnson or Jeremy Corbyn - to "lead the way" in reforming the institution.

The former soldier says peace on the European continent , externalcannot be taken for granted and Nato still has a vital role to play.

Image source, PA MEDIA

Sinn Fein's manifesto, external, launched earlier this afternoon, focuses mainly on Brexit and Irish unity - but what are the key pledges?

• Protect the Good Friday Agreement in future Brexit negotiations
• Continue the push for an Irish unity referendum
• Restore a credible Stormont executive
• Deliver an Irish language act and reform the petition of concern
• Implement the Stormont House Agreement

Sinn Fein is the second largest party in Northern Ireland after the Democratic Unionist Party (DUP) and it secured seven MPs at the last general election in 2017.

Its representatives do not take their seats at Westminster due to its policy of abstentionism.

The party's core belief is that Northern Ireland and the Republic of Ireland should be united as a single independent republic.

Here's our simple guide to Sinn Fein, in case you missed it.

Image source, PA MEDIA

The president of Sinn Fein has accused the Democratic Unionist Party (DUP) of using its "crazy" Brexit agenda as a badge of honour at Westminster.

Mary Lou McDonald was speaking at the unveiling of her party's general election manifesto, external in Londonderry.

The party's 15-page document focuses mainly on Brexit and Irish unity.

Addressing the manifesto event, Ms McDonald attacked the claim the solution to Brexit would only be found in the House of Commons.

Read our full story here.

The DUP has said it will seek further changes to Boris Johnson's Brexit deal, if he remains prime minister after the general election

Radio 4 PM

Radio 4's PM has been talking to the Liberal Democrat's Tom Brake about whether his party's support is being squeezed by the Conservatives and Labour.

Asked whether that could be due to the Lib Dem promise to revoke Article 50 - which would halt Brexit - Mr Brake says it does "require some explanation" - which is that revocation could only happen if the Liberal Democrats won a majority and therefore formed a government.

He points out that for the last two years the Lib Dems have also been campaigning for a "People's Vote".

He believes a referendum would be "appropriate" on the basis that "nobody was told" that Brexit - according to Boris Johnson's plans - would mean a border in the Irish Sea.

As for the polls suggesting that Lib Dem support is down, Mr Brake says they don't "pick up" what is happening in local areas and he points to the Lib Dems' campaign to unseat the Foreign Secretary Dominic Raab in Esher and Walton.

The Guardian

Image source, Police handout

David Merritt - whose son Jack was killed in the London Bridge attack - has written an article for the Guardian in which he says Jack would be "seething at his death, and his life, being used to perpetuate an agenda of hate that he gave his everything fighting against".

"We should never forget that," he says.

He describes his son as , external"proud", "absorbingly intelligent" and "fiercely loyal".

He was also "angry", David Merritt says, "because he saw our society failing those most in need. He was frustrated because the political elite have forgotten why it is important to be fair".

Read our full story on the political reaction here.

Radio 4 PM

The former Conservative Prisons Minister, Rory Stewart talks to Radio 4's PM about the London Bridge attack, calling it a "horrible tragedy".

Mr Stewart, who's stepping down as an MP at the election, says he would like to see debate about the attack removed from "big politics".

"It's always the right saying lock 'em up and throw away the key", he says, while the left wants to examine the "root causes" of terrorism.

One of the discussion points in the wake of the attack is whether it's possible to rehabilitate people. Mr Stewart says a "very focused individual approach" is required.

He adds that prison and probation officers have "the most difficult jobs on earth".

Image source, PA Media

More than 70 attack survivors have demanded that all political parties agree a "charter" protecting their wellbeing after the election.

They want quicker access to mental health support and faster compensation.

The group, which includes survivors of the 2017 Manchester Arena bombing and attacks in London, also says all venues must set up security plans.

Its demands follow Friday's London Bridge attack, in which two people were stabbed to death.

You can read the full story here.

The mother of a man killed in the Manchester Arena bombing told us why she signed a letter outlining the group's demands.

Figen Murray's son, 29-year-old Martyn Hett, was one of 22 people killed in the Manchester Arena bombing on 22 May 2017.

"I just want venues to be responsible for keeping their punters safe - and I want them to subscribe to mandatory security rather than just an option as it is at the moment," Ms Murray said.

She said bag checks and the use of metal detectors should also be stepped up.

Under "Martyn's Law", Ms Murray and the survivors' group want all owners of events spaces to be compelled to have a "basic security plan" in place.

Rory Cellan-Jones
Technology correspondent

Image source, Getty Images

The political parties' Facebook advertising campaigns have been lively enough since the general election was called a few weeks ago - but suddenly over the weekend they caught fire.

On Sunday, the Conservatives unleashed a tidal wave of adverts. Their two themes were getting Brexit done, and improving the NHS.

At one point, the Facebook Ad Library showed that about, external 2,500 adverts paid for by the Conservative Party were live.

Read the full story here.

Confused by the latest election developments? Got a question about polling or policy? Or is there anything else you'd like us to explain?

Send your questions to BBC News via the form on this page and we'll do our best to answer them.

Today we have been answering questions specifically about transport, like this one from Jenny:

Q - What is each party's position on HS2?

A - In August 2019, the government launched a review into whether to scrap HS2, the high-speed rail network.

HS2 is designed to connect London, Birmingham, Manchester and Leeds, cutting journey times with trains travelling at speeds up to 362km/h (225mph).

This will be published after the election but a draft copy of the review says it should go ahead. The first phase of HS2, linking London and Birmingham, was due to open at the end of 2026, but it could now be between 2028 and 2031 before the first trains run on the route.

The total cost has also increased from £62bn to between £81bn and £88bn in 2019 prices.

Boris Johnson has indicated during the campaign that he would be reluctant to scrap HS2. The Conservative manifesto says it will take the findings of the review into account, before making a decision.

Labour however, says it would complete a full HS2 line to Scotland. The Lib Dems say they would also support HS2, but want it to open as soon as possible.

The Brexit Party, Plaid Cymru and the Green Party have pledged to scrap the railway altogether.

The SNP don't mention the rail link in their manifesto.

You can read more questions on transport here.

And the parties' policies on transport in our manifesto guide here.

BBC News Channel

We catch up with our political correspondent, Ben Wright, on a train out of Southampton, where Boris Johnson has been campaigning this afternoon.

Ben says while the tour of the Port of Southampton gave the PM a chance to promote the Conservative Party's announcement of improvements to border security once Brexit has been delivered, that was not the focus of questions put to him by journalists.

As we told you in our earlier posts, Mr Johnson was instead asked about his response to a convicted terrorist killing two people at London Bridge on Friday.

Ben says Mr Johnson is "by no means rowing back on his focus on sentencing", because the PM feels the sentencing legislation in place when Usman Khan was jailed "was in part to blame" for him being able to carry out the attack

The political argument over this issue will "certainly rumble on", our correspondent says.

Security is likely to be a key focus for the Tories this week, he adds, with their announcement about borders today and the Nato summit on the horizon.

• Boris Johnson and Jeremy Corbyn attended a vigil for the victims of Friday's attack in London Bridge. A political row over why the attacker - convicted terrorist Usman Khan - was released from prison early is continuing
• Mr Johnson insists he has long argued against short sentences and early automatic release, and accepts that some prisoners "can't be rehabilitated"
• Mr Corbyn has pointed the finger at cuts to policing, probation and mental health services as contributing towards what happened
• Elsewhere, Nicola Sturgeon was interviewed on the BBC and refused to rule out taking legal action if a future Conservative government blocked a second vote on Scottish independence. She also faced questions on the NHS, trans rights, fishing and climate change
• The focus of Labour's campaign today is on transport, with the party pledging to cut rail fares by 33% and make train travel free for young people under the age of 16. BBC economics editor Faisal Islam says the announcement is significant - with Mr Corbyn promising to spend the money the previous government earmarked for a massive road building plan on public transport and cycling
• Meanwhile, the Tories are promising to improve the UK's border security by creating automated entry and exit checks and a requirement for biometric passports. Successive UK governments have attempted to introduce a more reliable system for counting people in and out of the country, with limited success
• UKIP has launched its manifesto - "Brexit and beyond" - criticising Boris Johnson's Brexit "treaty". Meanwhile, at Sinn Fein's manifesto launch, the party said it was ready to re-form the Northern Ireland Executive and wish to resume talks.

Actor Hugh Grant is on the campaign trail with the Liberal Democrats again today.

On Sunday, he was out with Luciana Berger and today he's accompanying Chuka Umunna, candidate for the Cities of London and Westminster.

Grant - who's been a vocal campaigner for stricter press regulation - tells supporters he's never been involved in a general election campaign before but thinks it's "different this time".

"I really think we're facing a national emergency. I don't think that what's left of the Conservative Party, once they've now expelled anyone who's was responsible or decent or sane, is something I could contemplate as a government of a country I love."

He says he's "banging the drum" for tactical voting and urging people to vote for the person with the best chance of unseating a Tory to "save the country".

According to the Financial Times journalist Sebastian Payne, Grant said he considered standing for Parliament himself, but added: "I talked to lots of people but in the end think I would struggle with party orders.”

Pat Mountain - the name of the interim UKIP leader - is trending on Twitter, after she launched her party's manifesto this morning.

Many people are sharing a video clip of an interview, external she gave to Sky News earlier, with some calling it a "car crash".

Among those who are critical of her performance is ITV's political correspondent Paul Brand...

Image source, Sky pool

More on that interview from the south coast with Boris Johnson a short time ago.

The reporter asks whether the real issue is not how long knifeman Usman Khan spent in jail, but why his de-redicalisation seemingly failed.

"That is a very profound question," Mr Johnson replies.

"When we look at some of the problems that we come across in trying to de-radicalise people, we have to face the grim reality that in some cases, it is really very difficult. And I think this was one of those cases."

The PM says it was "pretty obvious" that Khan was "not really a suitable candidate for automatic early release", but was nevertheless "sprung automatically" from jail, half way through his 16-year sentence for his part in a plot to bomb the London Stock Exchange.

Mr Johnson says it's "better for the protection of the public" to keep some offenders in jail for longer.

"It probably is true that some people can't be rehabilitated... there are unquestionably some cases that are just too tough to crack, and alas, [Khan] appears to have been one of them."

Here are a few key links to help you make sense of this story:

• Why was the London Bridge attacker out of prison?
• What is Learning Together?
• London Bridge sentencing row - who did what?

The BBC's economics editor thinks Labour's rail fares announcement today is a significant one - and suggests a very different set of priorities from the Conservatives.

A reminder that Labour is pledging to slash rail fares by 33%, simplify ticket prices for part-time workers and make travel for all under 16s free.

The Conservatives launched a bonanza of ads on Sunday.

Before then, the Tories had only spent about a tenth of the amount they spent in the 2017 election on online advertising.

They have typically been running fewer than 100 ads at any one time on Facebook and Instagram. Now they have 1,300 active ads - although that's still not as many as the Lib Dems have had.

The Tories' ads are mixed in content, but more than 250 concentrate on two of their most contentious policies - 50,000 "extra" nurses for the NHS, and 40 "new" hospitals.

Looking through the first 50 or so ads, they are directed at very small target groups - fewer than 1,000 people - and specifically aimed at either men or women. They're never designed for a mixed profile voter.

Meanwhile, one of the Conservatives' ads - which the BBC complained about - has been taken down by Facebook.