The BBC's assistant political editor tweets from the conference:

One Telegraph political reporter at the conference says her colleague was "spat at" by a protester while they were outside.

Mr Hammond says the government "will meet the 2% target for defence spending".

He said that makes Britain "the only major country in the world" to hit international targets both on defence and overseas aid spending.

Foreign Secretary Philip Hammond tells the conference: "Finally my first as a minister in a proper Conservative government."

Describing last week's Labour conference as "the 80s revival gig in Brighton" and the Liberal Democrat conference as a "party in a phone box in Bournemouth", he says: "We are going to show the British people what a real party of government looks like."

Lord Feldman of Elstree, chairman of the Conservative Party, opened the conference. Of the party's election victory earlier this year, he said:

The BBC's assistant political editor Norman Smith said: 

Image source, PA

Singer Billy Bragg warmed up the crowd of protesters in Manchester with a set on stage.

He changed the lyrics to his best-known songs to add topical references such as "take the money from Trident and spend it on the NHS" and "these Tory cuts will get me the sack".

You can watch events at the Conservative Party conference in Manchester as they happen by clicking on the Live Coverage tab at the top right of this page.

Foreign Secretary Philip Hammond, Defence Secretary Michael Fallon and International Development Secretary Justine Greening are all due to speak from 1400 BST. 

In the meantime, here is a rundown of today's main stories: 

• David Cameron tells the BBC's Andrew Marr Show cuts to in-work tax credits will go ahead despite calls from within his own party to think again 
• Mr Cameron announces a voluntary seven day contract for GPs in England
• Thousands of people attend an anti-austerity protest near the Conservative conference venue 
• David Cameron reveals, on the Andrew Marr Show, he would be prepared to use Britain's nuclear weapons
• He rejects an offer from Unite union leader Len McCluskey to accept higher strike ballot thresholds in return for allowing online voting, saying such a move would be open to fraud 
• Mr Cameron said he could not guarantee he'll get the changes he wants from his EU negotiations but there was nothing he could bring back that would satisfy some Eurosceptics in his party 

Shadow international development secretary Justine Greening has told the BBC that families on minimum wage will be better off despite plans to cut tax credits.

Image source, Getty Images

Speeches are due to start at 13:10 BST, with the rally expected to finish just after 15:00 BST. 

Those giving speeches include Frances O'Grady, general secretary of the TUC, and Len McCluskey, general secretary of Unite.

ITV political correspondent Paul Brand has this video, taken from the rally. It shows some SSI workers are among those taking part.

Redcar's SSI steelworks is to be mothballed, with 1,700 jobs lost.

People have been gathering for an anti-austerity protest in Manchester - held to coincide with the start of the Conservative party conference. 

The TUC says it expects between 50,000 and 80,000 people to attend, with unions Unison, the NUT, GMB, USDAW, RMT and FBU represented.

Image source, Getty Images

Here's David Cameron arriving for the first day of the Conservative Party conference. His speech will come on Wednesday, the final day.

This afternoon, the conference will hear from Foreign Secretary Philip Hammond, Defence Secretary Michael Fallon and International Development Secretary Justine Greening.

Mr Goldsmith also says he's promised his constituents to fight off the threat of a third runway at Heathrow - and adds that he doesn't think it is a "politically-deliverable project".    

And he says he would be "mad" not to speak to Australian strategist Lynton Crosby,  who is set to advise him in his campaign, describing him as a friend of his.

"His job is to ensure a campaign is organised and disciplined," says Mr Goldsmith, dismissing claims Mr Crosby is too controlling.

He added that the "campaign is led by the candidate, not the campaign manager". 

BBC Sunday Politics

Zac Goldsmith admits that standing for mayor of London was initially a "preposterous thing to even entertain".

"I did take some persuading," he adds.

The "extraordinary amount of support" he's had in London was enough to make him think he "wouldn't be wasting people's time", says Mr Goldsmith. 

He says Boris Johnson has a "fantastic legacy" as mayor. He wouldn't set out to be "Boris mark 2", describing Mr Johnson as "a unique figure in British politics". 

Earlier, David Cameron addressed concerns about tax cuts, saying other changes meant that working families on the minimum wage would be better off.

He rejected analysis by the Institute for Fiscal Studies (IFS) which said that was "arithmetically impossible". 

Deputy director of the IFS Carl Emmerson defended their work today, saying: "We stand by what we have said.

"Our analysis is there for everyone to see."

BBC Sunday Politics

Zac Goldsmith, Conservative candidate to be the new mayor of London, says he was "thrilled" to be selected. 

But he accepts that what he describes as "the Corbyn revolution" will make his job harder. 

"There's no doubt something extraordinary happened in the Labour party that no one had anticipated," he says, comparing it to a "tsunami". 

It's the reason, he thinks, that Sadiq Khan was elected as the Labour candidate.

A lot of people have been "animated" by what happened and will throw themselves into the campaign, Mr Goldsmith believes.

The unauthorised biography, due to be published tomorrow, came up earlier when David Cameron was interviewed by Andrew Marr. 

Mr Cameron said: "I think everyone can see why this book was written. The author wrote an article himself explaining why he was doing this."