Miliband, standing in for Starmer, starts with the environment, ahead of next week's COP 26 summit in Glasgow.

He says global emissions need to halve this decade if Britain is to meet its climate commitments - does the PM agree?

The PM says COP is very important for our planet and it is right to keep the 1.5C commitment alive.

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Kicking off PMQs in a packed House of Commons, Boris Johnson says the chancellor has updated the cabinet this morning on jobs and "rising productivity".

He also sends his best wishes to the leader of the opposition, and says his cabinet does the same.

Some news just in - Labour leader Keir Starmer has Covid and is isolating, so shadow business secretary, Ed Miliband is standing in and asking the first question.

Johnson has just stood up at the dispatch box. We will bring you all the exchanges between him and Starmer over the next 30 minutes...

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Prime Minister's Questions are due to start in a couple of minutes.

Boris Johnson and Labour leader Sir Keir Starmer will face each other in the Commons before Chancellor Rishi Sunak sets out his Budget and Spending Review at around 12:30.

We'll bring you live updates and analysis throughout.

Shortly, Chancellor Rishi Sunak will set out his Budget and the results of his Spending Review, which will detail how much government departments can expect to receive for the next three years.

The chancellor has just appeared outside Number 11, brandishing his ministerial red box on the way to the House of Commons.

What is happening and when? At 12.00 BST, Prime Minister Boris Johnson and Labour leader Sir Keir Starmer will face each other at Prime Minister's Questions. Then, at around 12.30, Sunak will deliver his Budget.

What do we know so far? The National Living Wage for people aged 23 and over will rise to £9.50 an hour, while a pay freeze on public sector wages will be lifted. The taper rate on universal credit is also expected to be cut, though government has ruled out a cut in VAT on energy bills. There will also be an allocation of £1.8bn for building around 160,000 new homes on brownfield sites in England.

Read here for a full list of what has been announced so far.

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So what is the relationship like between Boris Johnson at No 10 and Rishi Sunak at No 11 after months of Westminster rumours that there are tensions over spending?

The BBC's political editor, Laura Kuenssberg, tells Politics Live: "The mood music between the next-door neighbours is better than it was.

"But there is an ideological clash there."

The prime minister likes "big spending and big projects", while the chancellor "is, by nature, a fiscal hawk and very, very careful with money".

And there is wider unease in the Conservative Party as a whole, she warns, as the leadership tries to "squat in the middle of political road by taxing big and spending big", which is not their natural home.

Rishi Sunak has been giving a very upbeat message to his ministerial colleagues this morning, telling them his Budget "will deliver a stronger economy for the British people".

Downing Street says he briefed fellow cabinet ministers that the levelling-up agenda is the "golden thread" running through his approach.

Cabinet meetings are normally held on Tuesdays but it's a Budget tradition to gather the top team ahead of the chancellor's big moment in the chamber.

Rishi Sunak will be on his feet in Parliament in just under an hour to deliver his Budget statement.

Before that though, in about 15 minutes, Boris Johnson will host Prime Minister's Questions in the Commons.

Kevin Peachey
Personal finance reporter

Image source, Getty Images

For a set-piece event like today, it's easy to look Rishi Sunak’s announcements in isolation – and consider what they mean for your finances.

But remember, at the last Budget – not that long ago in March – the chancellor said income tax thresholds would be frozen for five years. That could be significant for anyone getting a pay rise next year and beyond.

However, there's a National Insurance increase coming in April to fund social care.

Taxes may not be altered in this particular Budget, but your tax bill will change in April anyway.

The BBC's business editor, Simon Jack, tells Politics Live that companies have felt "pretty bruised" in recent years, and not just because of the pandemic.

"There was the four letter dismissal of business fears from Boris Johnson," he says - we will let you work out what word that was - followed by the "the sticks and stones" of a rise in corporation tax, employers' National Insurance and the minimum wage.

"Businesses also feel they have been the punch bag and blamed for every shortage under the sun from HGV drivers to other labour shortages," he adds.

The government can of course point to all the wages they have paid out through the furlough scheme and the support they have offered in the past 18 months.

But Simon says businesses today are asking for no more taxes and a "more constructive tone" from Downing Street.

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It is now expected that the chancellor will announce changes to universal credit. Specifically, he could lower the taper rate, which would allow people to keep more of the money they earn as their working hours increase.

Under the current taper rate, claimants lose 63p in benefits for every extra pound they earn.

Karl Handscomb, senior economist at the Resolution Foundation think tank, says: "At the moment, workers receiving universal credit keep just 37p of every extra pound they earn – falling to less than 25p if they also pay income tax and National Insurance."

He says cutting the taper rate will help over two million people claiming universal credit.

But he adds: "Reducing the taper rate will help over two million families on universal credit. It won’t fully compensate the £20 a week cut – particularly for people who aren’t able to work."

Speaking on Politics Live, the BBC's political editor, Laura Kuenssberg, says there has been a "Budget buzzword bingo" in the lead up to today's speech, with Rishi Sunak promising "an economy fit for a new age of optimism".

Economics editor Faisal Islam agrees, and says the preview announcements "have been designed to sound as big as possible".

He says the £20bn of spending promises made ahead of the Budget will be stretched over a period of years and will be long-term investments, so may not make immediate impacts.

"And if you read between the lines, we might see a tight series of spending decisions they have made," he adds.

Faisal also says that the chancellor with his "new age rhetoric" is looking to move on from being "Emergency Rescue Rishi" to establish himself as the fiscally conservative chancellor he wants to be.

Adam Fleming
Chief political correspondent

It’s a tradition for the chancellor to have a big surprise at the end of his speech. Something that grabs all the headlines and distracts from any bad news.

And there’s lots of speculation that it could be something to do with the cost of living.

Yesterday, the Treasury appeared to be rejecting Labour’s call to reduce the VAT on domestic energy, saying that was poorly targeted and wouldn’t help the people that needed it the most.

Does that mean that there is another idea being worked on? Could there be concessions on the recent reduction to universal credit - as predicted by Manchester mayor Andy Burnham earlier?

The thing that will unlock this budget is not the budget document itself or the spending review, it’s going to be the economic forecast from the Office of Budget Responsibility.

The expectation is that the OBR is going to find the permanent effect of the pandemic on the economy are much less than was being predicted even just a few months ago.

That means Rishi Sunak could have more money to splash. The question is: who will benefit from the unexpected boost to the chancellor’s finances?

Like many in the hospitality sector, Guy Siddal, co-owner of Japanese restaurant Eatchu in Bristol, is struggling to recruit new staff and dealing with supply chain issues.

But he says what he would really like to see in the Budget is a break on tax rates. Before the pandemic, VAT was 20% but it was cut to 5% to help businesses. It was then lifted to 12.5% at the beginning of October.

"I would say I would certainly like to see the VAT rate stay at 12.5% for the hospitality sector," Guy tells us.

"Ideally I would like it to be rolled back to 5% because that was an incredibly helpful boost for us during what was an incredibly difficult year.”

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Northern Ireland’s Finance Minister Conor Murphy has played down expectations of significant extra money for Stormont as a result of the UK Spending Review, which will announced alongside the Budget today.

A Treasury document published in September suggests the devolved administrations can expect a 2.5%-3% real terms average annual increase in their block grants from 2021-22 to 2024-25.

Murphy says there is "little indication" that the government will "provide the investment needed to rebuild public services and spur economic recovery".

The outcome of the Spending Review will set the parameters for a three-year Stormont budget, with a draft budget expected to be published before Christmas.

We will be bringing you all the updates from Rishi Sunak's Budget speech here on the live page.

But if you fancy watching the action, BBC Two's Politics Live has a special programme to mark the occasion.

As well as the main event, you can expert to hear analysis from a range of BBC experts, as well as Treasury minister Simon Clarke and shadow chancellor Rachel Reeves.

You can tune in from 11:15 BST on BBC Two, and we'll also carry a live stream at the top of this page.

Today's Budget is a key moment for Rishi Sunak. The chancellor will set out by how much people will be taxed and what the money will be spent on.

It coincides with the conclusion of the Spending Review, which he launched back in September.

So what's the difference between the two?

Well, a Budget takes place once or twice a year, It deals with plans to cut or raise taxes for individuals and sets out how the revenue raised will be allocated over the coming months.

Spending Reviews, however, happen once every three years and set out longer-term plans for government departments. These plans outline how much money will be given to the government and to public services. This year's Spending Review will also set out the devolved administrations' block grants for 2022-23 and 2024-25 .

And he's off! Rishi Sunak is posing for pictures with his ministerial red box outside No 11 before heading to the Commons for his big moment.

Nick Eardley
Political correspondent

There has been plenty of speculation this morning about potential changes to the way universal credit operates.

Now, sources have now told the BBC that this speculation is correct.

Senior figures expect the chancellor to allow in-work claimants to keep more of the money they earn, by changing the taper rate.

Under the current taper rate, claimants currently lose 63p in benefits for every extra pound they earn.

The Treasury has refused to comment.

There is also speculation there may be other changes linked to universal credit, after lobbying by Tory MPs and others.

The decision to cut the £20-a-week universal credit increase, brought in to help low income families through the pandemic, was met with widespread criticism when it was withdrawn at the beginning of this month.

Read more on the end of the £20 universal credit boost here.

Val Hennessey, owner of International House Bristol, an English language school in the city, has told the BBC the government must give better guidance to local councils "so that they can give business rates relief to the English language teaching sector".

She says: “Schools have been denied relief so they’ve had to pay rates despite being closed during the pandemic and having an income drop of 84%."

Val adds: “We owe more money to Bristol City Council than pretty much anybody else. We also owe money to HMRC, we owe money on a Bounce Back loan, we owe money to our landlord.”

She says that while her local council as been "very sympathetic, they "do not feel that central government has been clear enough that they can offer this money to language schools".