It's the end of the day - which means it's time for a round-up of the main things you need to know from the Politics Hub.

• Sir Keir Starmer is en route to Washington DC as you read this for his first NATO summit, where he'll meet world leaders including Joe Biden;
• Our US correspondent Mark Stoke says he goes on the trip in a "much stronger position" than many of his allies, given his massive election win - we'll have live updates and analysis from the trip starting tomorrow.

• Back in the UK, parliament has returned and the Speaker re-elected, with the cabinet and shadow cabinet having been sworn in;
• Sir Keir Starmer welcomed the diversity of the new parliament in his first Commons speech as PM, while Rishi Sunak vowed the Tories would be an "effective and professional" opposition;
• The return of parliament allowed the Tories to elect the chair of their backbench 1922 Committee, which runs the party's leadership contests;
• But our political correspondent Darren McCaffrey is getting the sense from Conservatives that the contest may not happen for several months, as the battle for the soul of the party commences.

• Elsewhere, Health Secretary Wes Streeting says he's "optimistic" after his first meeting with representatives of junior doctors, as he seeks an end to the pay dispute that has caused industrial action;
• Our political correspondent Tamara Cohen said there may only be "a matter of weeks" to find an agreement before the BMA union holds a vote on holding more strikes.
  

That's it for our final bulletin of the day - stay with us for more news and analysis through the evening.

A former army chief has warned members of NATO the world is facing "as dangerous a moment as any time that we've had since 1945" as he called on members to invest more into their arms.

General Sir Patrick Sanders, who served as chief of the general staff until last month, told The Times that Russia, China and Iran were the "new axis powers", and a third world war could break out within the next five years if action was not taken.

Arguing the countries posed even more of a threat than the Nazis in 1939, he said: "They are more interdependent and more aligned than the original axis powers were."

But the military expert said the conflict was not a foregone conclusion if NATO members, including the UK, significantly improved their arms.

You can read more from Sky News:

The UK's newest MPs might have spent the last six weeks fighting for a place in parliament - but it can still be a shock to the system once they enter it, according to those familiar with the process.

That's why House of Commons staff have spent months preparing for their arrival, working on everything from buddy schemes to starter packs and photobooks to help them get to grips with the job.

This secret team of helpers is not messing about. In fact, the first contact parliament has with newly elected representatives is at the election count itself.

Read all about how new MPs are prepared for the job here:

After the Conservative Party lost the general election, Rishi Sunak announced he would resign as leader "once the formal arrangements for selecting my successor are in place".

So how could the next leader be selected?

1922 committee

The body that governs Tory party leadership races is their backbench committee of MPs, the 1922 Committee.

Today, Tory MPs elected a new chair - Bob Blackman.

Decisions can now be taken about the timeframe and process of the leadership contest - although it is unclear when that will happen.

Rishi Sunak's role

As it stands, the former PM remains leader of the party and leader of the opposition. He has appointed a shadow cabinet and will fulfil the constitutional requirements of the role - for now.

Mr Sunak could agree to stay as party leader until a permanent successor is selected - in which case he will continue to carry out the opposition leader role, including facing Sir Keir Starmer at PMQs.

But he could choose to step down before the contest is concluded, which he seemed to suggest in his resignation speech, which would mean an interim leader would have to be chosen (that would likely fall to Oliver Dowden, who is the interim deputy leader).

Will the party members have a say?

There appears to be broad consensus among Tory MPs that members should get a vote on who the new party leader should be.

Short vs long

Some Tories have proposed the contest should be short, so the new leader can be in place to challenge the Labour government as soon as possible - particularly when they present their first budget in the autumn.

However, a consensus appears to be emerging that a long leadership contest is the right thing to do to ensure there is full debate on which direction the party should take.

It could mean that nominations for the new leader don't even open for a number of weeks, and then MPs could whittle down the number of candidates - or not, and members could choose between multiple people.

There have been suggestions that the contest should not conclude until after the party's conference in early October, like when David Cameron won back in 2005.

By Mark Kleinman, City editor

The boss of Hakluyt, the corporate intelligence firm, is being lined up for a top business role in Sir Keir Starmer's fledgling Labour administration.

Sky News has learnt that Varun Chandra, who has been Hakluyt's managing partner since 2019, is in advanced talks to join the government.

Sources said on Tuesday that he was likely to take on a senior business liaison role in 10 Downing Street - a role occupied by Lord Petitgas, the former Morgan Stanley banker, in Rishi Sunak's administration.

Like Lord Petitgas, Mr Chandra is an ex-Lehman Brothers banker who went on to establish the regulated business operations of Tony Blair, the former prime minister.

You can read more from Sky News here:

The UK is in a relatively unusual position as Sir Keir Starmer jets off for his first NATO summit as prime minister.

Given the struggles of Joe Biden, Emmanuel Macron, and some other Western leaders, our US correspondent Mark Stone says the prime minister comes to Washington DC looking relatively strong given his enormous election win.

"Politically he is in a much stronger position than many colleagues he will meet," says Mark, who'll be at the summit.

Sir Keir will be among the leaders of the 31 other NATO members for a summit being described "as the biggest event of its kind for three decades" given the ongoing war in Ukraine.

Mark says that sometimes in politics "timing is luck" - "and it's certainly luck for Starmer that so soon after he took office, he is in Washington".

He'll also meet Joe Biden at the White House while he's in town.

That concludes our coverage of tonight's Politics Hub programme - it will be back again from 7pm tomorrow. Stay with us here for more news and analysis through the evening.

Our political correspondent Darren McCaffrey is outside The Spectator's depressingly rainy summer party in London - and it doesn't get more "establishment" than this, he says.

Plenty of senior Tories are there, and so is Nigel Farage.

Darren notes that although the new chairman of the 1922 Committee was confirmed as Bob Blackman tonight - the timing of a Tory leadership contest remains unclear.

"The conversation is not tonight about who should take over the Conservative Party, it's much more about this process," Darren says.

"Whether this leadership contest needs to be sorted as soon as possible - ahead of the party conference - or whether the Conservative Party should do what they decided back in 2005."

That was a really long campaign, one which ended with David Cameron taking the reins.

Darren says the consensus at the party seems to be the Conservatives need to have a think - and they need a long time, certainly until the summer has been and gone.

It means Rishi Sunak could still be leader for months to come.

Housing minister Matthew Pennycook is now asked about  Labour's decision to take "Levelling Up" out of his department's name.

It is now the Ministry of Housing, Communities and Local Government.

Boris Johnson didn't take well to this decision, accusing the new government of a lack of ambition.

Mr Pennycook says this is "nonsense", adding: "I'd expect nothing less from the former prime minister."

He said the way the Tory government had approached levelling up was a "gimmick", with communities "held back" and "forced to bid" for "small pots of money" from Whitehall.

"We are taking a whole government approach to regional inequality," says the minister.

"It's got to run through everything we do, so the ambition remains the problem, if you like. The diagnosis was right. 

"We want to get back to basics."

Housing minister Matthew Pennycook is joining Ali Fortescue on the Politics Hub.

Regarding his brief, he admits the government's goal of building 1.5 million homes this parliament is a "very stretching target".

"We think it's absolutely necessary because we've got an acute and intensifying housing crisis," he says.

Private developers will play a major role, of course, but he says councils will have a "greater part" too.

'Capacity issue' in workforce

Ali points out there may need to be a major training drive to make the housebuilding ambition viable.

Mr Pennycock says the previous government was right to introduce a temporary work visa to bring more construction workers in from abroad, but said we need more home-grown builders too.

He admits there's a "capacity issue" at the moment, on both the "construction side and planning side", which the government will "take steps to address".

The House of Commons returned today - and the rarely seen magic of our political system unfolded before our eyes.

Power was transferred from one party to another - not only without a shot being fired, but without even a voice raised in anger. 

Instead, the changing of the guard was signified by the simple act of sitting in a different part of a small chamber in Westminster.  

From Rishi Sunak - on the opposition benches for the first time in his career - a sombre concession of defeat and a pledge that the new Conservative opposition would hold the government to account.

Change was everywhere you looked - more women MPs, the most diverse Commons ever and a Liberal Democrat party taking up the most room of any third party in a hundred years. 

The future represented by the more than 300 people setting foot in the Commons chamber for the first time - including Nigel Farage.  

But so was the institutional memory of the House: Sir Edward Leigh, the new Father of the House after 41 years of service.

And Diane Abbott, the new Mother of the House to whom Sir Keir Starmer paid tribute as someone who had fought for a parliament that truly represents modern Britain.

Soon regular service - the political pantomime, jeering, and theatrics - will doubtless resume. 

But today, for a brief moment, we witnessed parliament at its best.