The chancellor unveiled a new "UK digital services tax" aimed at tech giants, which are profitable and generate at least £500m a year in global revenues.
Promising a Budget for "Britain's future", Mr Hammond also earmarked an extra £1bn for the Ministry of Defence and set out the government's plan for the NHS, including £2bn per year for mental health services.
In addition, he said the government would never sign another private finance initiative (PFI) deal, long criticised for locking the taxpayer into hugely expensive infrastructure contracts that enrich private firms.
He also promised an additional £1bn for the implementation of universal credit, which also faces widespread criticism for pushing vulnerable people into homelessness and food bank dependency.
See below for live updates
Good morning, and welcome to The Independent's live coverage of the Budget 2018. We will be bringing you updates throughout the day as chancellor Philip Hammond delivers the last budget before Britain is due to leave the European Union in March next year.
Philip Hammond is due to present the Budget at 3.30pm on Monday. The announcement traditionally comes on a Wednesday, although this year that would have meant the chancellor delivered his speech on Halloween, a potential gift for headline writers. The government has however denied this is the reason for the break in protocol.
So what is likely to feature in this year's Budget? The Independent's associate editor Sean O'Grady talks to deputy political editor Rob Merrick and acting business editor Caitlin Morrison about what to expect.
The chancellor will walk into the Commons today boosted by a £13bn windfall provided by better-than-expected government borrowing figures.
This means he will be afforded the opportunity to announce additional spending in a number of areas.
Among the headline announcements expected from today's Budget is an additional £2bn investment from the government in mental health services.
Billions of extra funding is also likely to be announced for road improvements, broadband, social care and help for small retailers.
However, Mr Hammond says plans for additional government spending would have to be torn up and re-thought if Britain crashes out of the European Union without a deal.
The chancellor has admitted the UK would need to take a "different approach" if negotiators are unable to reach an agreement with Brussels on the terms of the country's withdrawal from the bloc.
Labour MPs have claimed this new direction could mean turning Britain into a low tax, low regulation economy similar to that of Singapore.
On ITV"s Good Morning Britain, Justine Greening, the former Tory education secretary, suggested she could run in the party's next leadership contest.
She told the programme: "We need a guarantee on opportunity for people in this country in the same way that we try to give them guarantees on health and guarantees on dignity if they are falling out of work."
In response to the suggestion that sounded like a leadership manifesto, she said: "Things need to change, don't they, and I think people need to have some hope for the future, that Britain can be a country that runs differently and more fairly than it does at the moment."
Asked if she would run if there was a vacancy, the Putney MP said: "I might be prepared to, but I'm more interested in the Conservative Party actually showing what it can do for this country.
"Yes, we spent a lot of time having to fix the nation's finances but what we now need to do is discover - maybe rediscover - our own mission, which has got to be about how we make sure that young people growing up everywhere in this county have the same access to opportunity and it shouldn't matter whether they have got parents who are maybe middle class, a bit more sharp-elbowed.
"Talent is spread evenly. The challenge of Britain is that opportunity isn't. That's what we have got to fix."
Green campaigners have lined up to attack chancellor Philip Hammond for announcing a multi-billion-pound boost for building and upgrading roads – days after world scientists urgently warned that greenhouse gas emissions must be cut.
In today's Budget, Mr Hammond is due to champion £30bn of funding for new roads and road repairs, hailing it “the biggest-ever cash injection for England’s largest roads”.
Deputy speaker Lindsay Hoyle has got his hands on a copy of the Budget - but he's keeping it under wraps until 3.30pm, when the Chancellor gets to his feet.
The EU said there were no plans to mint a special euro coin to mark Brexit after reports that a commemorative 50p would be released in the UK.
A European Commission spokeswoman said: "We have no current plans to do anything of the sort."
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