Theresa May has said she will she will keep the controversial target for minimum spending of billions on foreign aid at her latest campaign stop today.
The Prime Minister said it was important to ensure the money - equivalent to 0.7 per cent of national income and more than £13billion last year - is spent properly.
But as she returned home to Maidenhead for the first time since calling a snap general election, Mrs May ended speculation she would dump the controversial policy.
The dramatic development on the election trail came after Nicola Sturgeon launched a new broadside at Mrs May for trying to 'crush dissent' by chasing a landslide election win.
Meanwhile, Labour leader Jeremy Corbyn is banging the drum for his new commitment to cut class sizes in schools with a tour through the south.
David Cameron ran twice on the promise to spend 0.7 per cent of national income on aid and the target was first met in 2013. Britain is just one of six nations to meet the international goal.
But many Tory MPs hate the commitment, which is written into law unlike any other spending, particularly at a time of austerity elsewhere.
Mrs May confirmed the pledge in a rare question and answer session with reporters.
Speaking from a toothpaste factory in Maidenhead, Mrs May said: 'Let's be clear, the 0.7 per cent commitment remains and will remain.
'What we need to do is look at how that money is spent and make sure that we are able to spend that money in the most effective way.
'I am very proud of the record we have, of the children around the world who are being educated as a result of what the British taxpayer is doing in terms of its international aid.
'I was in Jordan a couple of weeks ago, in a school, meeting children who were being given a good quality education. It's one of the things the UK is providing.
Microsoft billionaire Bill Gates yesterday urged Mrs May to stand behind the target, insisting it saves lives.
He was slammed by Tory MP Philip Davies and told to 'mind his own business'.
A group of charities including Save the Children, Unicef and Oxfam, and the former Archbishop of Canterbury Rowan Williams weighed in behind Mr Gates today.
The Taxpayers' Alliance today condemned Mrs May's promise as the 'wrong' thing to do.
Chief executive John O'Connell, Chief Executive of the TaxPayers' Alliance, says: 'The 0.7% foreign aid target is totally arbitrary and meaningless and it is disappointing that the Prime Minister has refused to see sense and scrap the ring fencing of the budget.
Former Chancellor George Osborne welcomed Mrs May's commitment, tweeting: 'Re-commitment to 0.7 per cent aid target very welcome.
Mrs May used the visit to Maidenhead reiterate her message that the election is about ensuring Britain has 'strong and stable leadership' going into Brexit negotiations.
Theresa May headed home to Maidenhead today on the third day of her election tour.
After two days spent in the battleground seats of Bolton and Enfield North, she said she wanted to explain to her home seat why she was campaigning.
The Conservative campaign is targeting scores of Labour constituencies that backed Brexit.
She told workers at the GSK Factory she wanted to come early in her election campaign back to Maidenhead, the town she has represented in Parliament since 1997.
She added: 'The election campaign has only just begun, I'm not taking anything for granted, the result is not certain.
'I'm going to be out and about campaigning across the whole of the United Kingdom and I'm going to be out and about campaigning and meeting people in all different communities across the United Kingdom.
In answer to other questions, Mrs May failed to give a firm commitment to continuing the so-called 'triple lock' on pensions.
The promise, made under the coalition, guarantees pensions rise by 2.5 per cent, the increase in wages or inflation - whichever is higher.
The pledge, which is set to be backed by Labour at the election, is controversial as it means pensioner households are better off than working households.
Asked if she would promise to back the triple lock again, Mrs May said: 'What I would say to pensioners is just look what the Conservatives in government have done.
'Pensioners today are £1,250 better off as a result of action that has been taken.
Asked why she was refusing to take part in TV debates with other party leaders during the election campaign, Mrs May said: 'I've been doing head-to-head debates with Jeremy Corbyn week in and week out since I became Prime Minister.
Philip Hammond has hinted that the Tories could raise taxes after the election - just a month after he was forced into a humiliating U-tun over proposed national insurance hikes.
Theresa May told her Chancellor to abandon the £2billion tax raid after a massive backlash over the policy, which breached the party's manifesto promise not to rise income tax, national insurance or VAT.
But Mr Hammond has suggested the party could abandon its commitment to the triple tax lock for the June 8 election.
Speaking at the IMF's spring conference Washington, he said the pledge has limited his ability to raise cash to pay off the deficit.
But his comments are likely to anger voters as they raise the prospect of a post-election tax raid.
He said: 'I’m a Conservative. I have no ideological desire to to raise taxes. But we need to manage the economy sensibly and sustainably.
Nicola Sturgeon has accused Theresa May of wanting to 'crush dissent' as she claimed Scots must choose between Brexit-obsessed Tories and the SNP at crucial elections.
The SNP leader admitted it was likely Mrs May would be returned to No 10 on June 8 but said voters must constrain her chance to 'steamroller' opposition.
The First Minister made her latest intervention on the national campaign as she launched her manifesto for the Scottish local elections on May 4.
The town hall polls are the biggest day of the campaign between now and June 8 and the results will shape the final month of the general election battle.
Ms Sturgeon's remarks come after it was claimed Jeremy Corbyn's Labour would try and get into No 10 with the backing of the SNP and Lib Dems if it manages to stop the Tories winning a majority.
Mrs May hit back at her latest campaign visit today as she told workers in Maidenhead her new Government would push back at the 'separatists who want to break up the UK'.
Labour's first target is to stop a Tory majority so it can try to form a minority government with support from the SNP and Lib Dems, sources have claimed.
Jeremy Corbyn's campaign believes it is possible to take 40 Conservative marginals on June 8, destroying Theresa May's current slender majority.
The Tories would still be the largest party but in a hung parliament, Mr Corbyn could enter Downing Street with informal backing from the SNP, Liberal Democrat and Green MPs.
The claim, made by campaign sources to the Daily Mirror, is in defiance of polls suggesting a landslide victory for the Conservatives.
And it will fuel Tory warnings that a vote for Labour is a vote for a 'coalition of chaos' driven by Nicola Sturgeon.
Mr Corbyn scrambled to rule out the idea of a formal coalition with the SNP earlier this week after leader Nicola Sturgeon backed a 'progressive alliance'.
The prospect of the SNP in power in London is toxic to English voters and was a huge driver of the Conservative campaign in 2015.
Ms Sturgeon intervened again today to warn the local elections in Scotland were a choice between Tories who believe in nothing but Brexit and the SNP.