Ruth Comerford
Live reporter

The day started with the German Chancellor Friedrich Merz's descent into the UK's Stansted airport, and culminated with both nations signing their first treaty since World War Two.

Parts of the treaty highlight the need for greater co-operation between the two countries, against a backdrop of the US's changing tune to Nato and Russia's continuing war in Ukraine.

The UK and Germany "mean business" on tackling illegal migration, Starmer said, as he welcomed Merz's commitments to tackling people-smuggling gangs and stopping small boats.

A host of other pledges - including co-operation on security and defence, bilateral trade and scientific research - were also promised in the treaty.

By next month, some UK passport holders will also soon be able to use German e-gates, and there are pledges on school trips and train links due to come into force in the next decade.

Signed in London's Victoria & Albert Museum - chosen to highlight the historic relationship between the UK and Germany - the Kensington Treaty is proof Germany and the UK are "really on the way to a new chapter," Merz said.

We're ending our live coverage, but in the meantime you can read all the latest in our main news story.

At this afternoon's press conference Prime Minister Keir Starmer confirmed that a plan was in place in the event of a ceasefire in Russia’s war on Ukraine.

We now have more detail about what that plan will entail.

UK Defence Secretary John Healey has told the House of Commons detailed military plans have been drawn up for a multinational force to support Ukraine if a ceasefire agreement is signed.

Ukrainian troops would lead the defence of their country, while the multinational force would provide logistics, armament, and training experts.

The force will include a 3-star multinational command headquarters in Paris, which will rotate to London after 12 months.

Once deployed, there will also be a coordination headquarters in Kyiv headed by a UK 2-star military officer.

The force aims to secure Ukraine’s skies, using aircraft to deliver levels of support similar to Nato’s air policing mission.

Healey said more than 200 military planners from 30 nations have worked intensively on the plans over recent weeks including visits into Ukraine led by UK personnel.

Keir Starmer and Freidrich Merz just held a joint news conference, hailing the newly-signed agreement between the UK and Germany. Here are some of the key topics they spoke about:

Greater co-operation

Starmer talked about the treaty as a "shared resolve" while Merz welcomed it as a "new chapter". British and German industries will "better leverage their strength" together, Merz said, as Starmer welcomed investments in the UK he said would be worth £200m.

Immigration

Starmer said the agreement shows "it's clear we mean business" on disrupting irregular immigration and thanked Merz for introducing a new law in Germany that will allow small boats stored there to be seized. Merz said there needs to be a complementary agreement between the UK, France and Germany to address the issue.

Defence

Security is the thread running through this treaty, Merz said, pointing to Nato commitments and defence co-operation. He said the agreement includes weapons development, strengthening deterrence and protection of the North Sea.

Ukraine

The pair were asked about support for Ukraine, to which Starmer said the first step is to get Putin "to the table for an unconditional ceasefire". Merz said the pair have discussed military support to Ukraine, but wouldn't speak publicly about specifics.

Brexit

Merz was frank about his feelings on the impacts of Brexit, saying he personally "deplores" Britain leaving the EU and that greater youth mobility between the UK and Germany has, to his "pleasure", been agreed.

Treaty sends important signals about shared prioritiespublished at 16:25 British Summer Time

16:25 BST

Damian Grammaticas
Political correspondent

Flying around are a lot of big claims that what’s been agreed in today's treaty is “historic” and “ground-breaking”, hyperbole aside does it live up to that?

Well, in the broadest brush sense, yes. As the German chancellor noted, it’s the first such treaty the UK and Germany have signed since they fought in the Second World War.

In truth some of the things the two sides are highlighting aren’t exactly new. The pledge to defend each other in case of an attack is already a Nato commitment.

Other things that aren’t new are that Germany will change its laws to make it easier to seize boats for use by people-smugglers in the Channel, which was agreed before today - and through its deal earlier this year with the EU, the UK had already secured a commitment that countries would open more e-gates to British travellers.

But there are specific areas where the treaty has practical consequences, joint defence projects, a push to try to increase exports to third countries of jointly-produced weapons such as fighter jets and armoured vehicles, and joint green energy projects in the North Sea.

And more important is the fact the treaty sets in place a whole system of annual meetings of ministers and officials, in defence, security, finance, home affairs, investment and more to co-ordinate policies. On top of that the leaders will meet every two years to set out an action plan.

That sounds like dry stuff, but it sends important signals through government structures and business about the shared priorities and shared intent here.

Of course there was far deeper and more structured co-operation when the UK was a member of the EU. In that sense this treaty isn’t historic. But it is building new forms of co-operation and the processes to make that work.

The conference has now come to an end after Prime Minister Keir Starmer and German Chancellor Friedrich Merz signed the biggest treaty between the two countries in 80 years.

Stay with us as we continue to bring you updates.

Image source, PA Media

Digging into the specifics on defence for Ukraine, a Bloomberg journalist asks about peacekeeping forces in Ukraine - and whether this is a "realistic" option.

Starmer says the first thing to do is to get Russian leader Vladimir Putin "to the table for an unconditional ceasefire".

He says sanctions might play a role, and that the aim of the coalition of the willing is to ensure a ceasefire isn't breached by Russia to provide "lasting" peace.

He confirms military plans include support by land, sea and on the ground - including sending troops to Ukraine.

"The military plans are now as developed as they need to be," he says.

Politico journalist Anne McElvoy from Politico next asks the European leaders "what difference" the treaty will have on the war in Ukraine as defence projects like missile development will take years to complete.

She questions Starmer, asking if he has been putting pressure on Merz to deliver Taurus missiles into the battlefields.

Starmer says as the UK and other European countries ramp up defence spending, it needs to be seen as not just a spending issue.

He acknowledges there is longer-term work to do following the treaty, but says it sets up a framework for co-operation.

Merz says they discussed military support to Ukraine, like air defence and capabilities to carry out deep strikes.

He says those capabilities will be delivered soon, but declines to speak publicly about what exactly that will entail.

Image source, PA Media

Answering a question on migration, Merz says his government has "taken another step" following on from the last German government's administration and that numbers of irregular migration are going down.

He says numbers are down 25% in this quarter compared with the same period last year.

Merz says efforts to tackle the issue have increased, however, "we don't want to damage the Schengen area", nor the single market.

He says he talked to Starmer this morning about common rules to better protect the border of the EU, and that co-operation between the UK and France needs to be complemented by an agreement between all three nations to reduce irregular immigration.

We are on the right path, but not there yet, he says.

The leaders are taking questions now - the first is from Sky's political editor Beth Rigby.

Addressing Starmer, she asks as Trump has signalled he's prepared to sell more weapons to allies of Ukraine, will the UK be involved, and will this be a game changer?

Starmer says he is "discussing it closely" and "is working hard with the US" on this. He adds this shows the strength of the UK, France and Germany co-operating.

Merz zeroes in on defence, saying that today's treaty builds upon previous agreements in developing weapons and strengthening deterrence. He adds that it includes making sure that the North Sea is better protected and there is work along the eastern flank of Nato and co-operation for support for Ukraine.

To economics, he says the agreement will boost economic growth, and that British and German industries will together "better leverage their strength".

The German chancellor also welcomes the agreement on youth mobility, saying that it is "here that Brexit has been painfully evidenced in the past years" and that it is to his "pleasure" that school groups will be able to travel without passports or visas.

Merz is speaking about Ukraine now and praises Donald Trump after the US leader said he would send weapons to Ukraine via Nato earlier this week.

He says this will increase the pressure on Vladimir Putin to finally negotiate peace.

"Europe and the United States are pulling in the same direction here," he says.

Image source, PA Media

Merz says the reason the two signed the treaty at the Victoria & Albert Museum in west London earlier is because it is a nod to the enduring relationship between Queen Victoria and her German-born husband Prince Albert.

He says he hope this tradition will shape the treaty for many generations to come.

He adds that security is the "thread running through the treaty", as he describes the assurances to assist one another in case of attack, reaffirming Nato commitments between the two countries.

Hailing improved cooperation between the UK, Germany and France, he says the three nations are converging on security, migration and economic policies.

Image source, UK pool

Starmer hands over to Merz, who says he is "really proud and happy to be here today".

The German chancellor says this is a historic day, saying "we are really on the way to a new chapter".

He then switches to speaking in German, and says that both nations must "respond to the major challenges of our time".

He says Russia is "shaking the European security architecture" and that transatlantic ties are undergoing a "far-reaching transformation like we have not seen for a long time".

Merz adds that today's agreement is about securing the freedom, security and prosperity of the people of both our countries.

Starmer goes on to say they are working with Germany to tackle illegal migration.

He thanks Merz for taking decisive action to strengthen German law so that small boats being stored in Germany can be seized, "disrupting the route to the UK".

"It's a clear sign we mean business," he says.

Starmer moves on to say the two have also discussed the "appalling situation in Gaza". He adds they are calling for the release of Israeli hostages held in the territory and for the delivery of humanitarian aid.

He then moves on to talk about the war in Ukraine and says they are working with allies to boost military support to the country.

Starmer says the newly-signed treaty commits both countries to improve defence spending, bring industries together to boost exports and improve technology development.

Mentioning a new business forum and a direct rail link, the prime minister says this will facilitate better access between Germany and the UK.

He adds this means new investments in the UK "worth over £200m" and delivering on new infrastructure projects including in North Sea energy.

Image source, UK pool

UK Prime Minister Keir Starmer kicks off the news conference, welcoming German Chancellor Friedrich Merz to the UK and saying the pair "see the scale of the challenges our continent faces today and we intend to meet them head on".

Starmer says there are also opportunities and that he and Merz have a "shared resolved to share this new era" with their leadership.

He adds that today's treaty is the first ever major bilateral treaty between the UK and Germany, which he describes as "two great modern European nations".

He says that it's an expression of shared aims and values, and that it contains 17 major projects "where we will come together to deliver real results".

Image source, UK pool

We are now hearing from Prime Minister Keir Starmer and German Chancellor Friedrich Merz following their signing of the biggest treaty between the two countries since World War Two.

Starmer is first up. Stay with us as we bring you all the key lines and you can watch live above.

Germany sees opportunity to reset UK relationspublished at 15:32 British Summer Time

15:32 BST

Damien McGuinness
Berlin correspondent

The result of the Brexit vote nine years ago surprised, disappointed and even shocked many Germans, including the new Chancellor Friedrich Merz, a keen supporter of the European Union.

The traditional view of the UK in Germany was of a pragmatic, business-orientated trading nation. Leaving the EU was widely seen here as an illogical act of self-harm that damaged trade.

German-British trade links withered and the political turmoil in Downing Street after the vote meant that the UK was increasingly viewed as a country that was difficult to deal with.

Berlin believes Keir Starmer’s government is less antagonistic towards the EU than previous British administrations.

Given the global challenges facing Europe, from the war in Ukraine to erratic policy-making in Washington, Germany now sees an opportunity to reset relations with the UK, with the aim of boosting trade and easing barriers to travel.

The prospect of increased defence cooperation is also key.

But such commitments are unlikely to provide a huge economic boost: the biggest trade benefits come with being in the EU’s customs unions - something ruled out by Starmer.

Image source, EPA

UK Prime Minister Keir Starmer and German Chancellor Friedrich Merz agreed on a "first of its kind" deal on defence, migration, the economy and climate.

Shortly we'll be hearing from the leaders themselves, but until then let's take a look at what was agreed.

The treaty suggests Merz will allow some UK citizens to use e-gates on arrival into Germany, something that's not been possible since Britain left the EU. It also puts into place plans to discuss setting up a direct rail link between both nations.

Germany and the UK will also work together to tackle cross-border crime, in a bid to curb the number of people smugglers who prey on asylum seekers trying to reach Europe - especially those who attempt to get people across the channel in small boats.

Defence is another priority for the two nations, as they pledge to pursue "deep exchanges" on security issues such as arms policy and nuclear threats.

Cooperation in science and technology initiatives and support for youth mobility and education schemes are among the areas of collaboration between the two countries.

Germany and the UK also reiterated their commitment to limit global warming to 1.5C above pre-industrial levels, as laid out in the Paris Agreement on reducing the impact of climate change.

Image source, EPA

We're expecting to hear from Keir Starmer and Friedrich Merz in a joint news conference at 15:30 BST.

The last we saw of them was after they signed the treaty and headed into No 10 for private talks.

We'll bring you the key lines right here and you can watch along via the watch live button at the top of the page. Stay with us.