David Cameron has hailed the "political will" shown at the anti-corruption summit he is hosting in London
The prime minister said it was "the biggest demonstration of the political will to address corruption that we have seen for many, many years".
The summit has brought together 12 heads of state and government and a total of more than 40 countries - including Nigeria and Afghanistan, who Mr Cameron branded "fantastically corrupt" in a gaffe, earlier this week.
"Today the world has come together in a coalition of the committed to expose, to punish and to drive out corruption," Mr Cameron said in a speech at the end of the day's proceedings.
Attendees had shown "far more political will not just for words, but for action that will make a difference", he added.
"There is nothing as powerful as an idea whose time has come, and I believe that is the case with fighting and driving out corruption."
Prime Minister David Cameron has opened the anti-corruption summit in London, with a call "to keep challenging ourselves to ask ourselves what we can do to expose corruption".
PM: At this summit, we want to keep challenging ourselves to ask ourselves what we can do to expose corruption #AntiCorruption
I believe that corruption is the cancer at the heart of so many problems we need to tackle in our world.
Why is it happening? Who is going? And will it get awkward after the Prime Minister's 'corruption gaffe'?Read the full story ›
David Cameron has praised Nigeria and Afghanistan for the action they have taken in combating corruption.Read the full story ›
The Nigerian President has issued a statement through his spokesman saying David Cameron's remarks about Nigeria are "embarrassing", and that he must be looking at an "old snapshot of Nigeria."
This is embarrassing to us, to say the least, given the good work that the President is doing.
The eyes of the world are on what is happening here.
The Prime Minister must be looking at an old snapshot of Nigeria.
Things are changing with corruption and everything else.
David Cameron has caused controversy after he was filmed telling the Queen that Nigeria and Afghanistan are "fantastically corrupt," ahead of an anti-corruption summit.
David Cameron's comments about corruption in Afghanistan are "unfair", a spokesman for the Afghan embassy has said.
The spokesman said: "President Ghani and his Government since in office have taken major steps to fight corruption.
"Countering corruption is a top priority along security issues for the National Unity Government.
"We have made important progresses in fighting systematic capture in major national procurement contracts and are making progress on addressing institutional issues as well as issues related to impunity.
"Therefore calling Afghanistan in that way and taking bold decisions by NUG is unfair."
Britain must get its house in order as well as helping to tackle corruption abroad, a group tackling global financial corruption has told ITV News.
Responding to David Cameron's comments about Nigeria and Afghanistan, Robert Palmer of Global Witness said: “Nigeria and Afghanistan are both deeply corrupt countries, but their leaders have shown signs that they want to clean up their act.
"They are not helped by the secrecy sold by UK tax havens or the army of lawyers and bankers from places like London willing to handle stolen money or look the other way - we must get our own house in order too."
David Cameron's comments on corruption in Nigeria and Afghanistan are "very unhelpful and deeply regrettable", Nigerian poet and novelist Ben Okri has told ITV News.
Mr Okri said he was "appalled and rather surprised" that the prime minister would make the remark, saying it sent out the wrong signal and would damage relations between the nations.
Mr Okri, considered one of the foremost African authors, described the comments as "fantastically" unhelpful.
He said: "I'm rather appalled actually and rather surprised that a leader of an important world nation should be making that kind of remark to world. I think it sends a very wrong signal out to the world, I think it's a very discouraging remark."
He added that he thought Mr Cameron should apologise, saying: "I think he should make sensible amends."
David Cameron "has egg on his face" after being filmed telling the Queen there are some "fantastically corrupt" countries coming to a UK anti-corruption summit, Labour said.
The party likened the episode to another gaffe - when Mr Cameron was caught revealing how the Queen "purred" with pleasure when he told her Scots had rejected independence.
"This is another gaffe from the PM - you'd hope he'd have learned his lesson when it comes to off the record comments and the Queen but sadly not," Wes Streeting MP said.
"The fact that David Cameron has egg on his face shouldn't deflect from the more serious issue: for all his talk about corruption he's failing to act.
"If the PM really is serious about tackling corruption at the summit this week he needs to get his own house in order and make good on his promise to deliver public registers of beneficial ownership for the UK crown dependencies and overseas territories."
David Cameron's comments on corruption in Nigeria and Afghanistan are not "entirely helpful" ahead of Thursday's anti-corruption summit, Transparency International has said.
A spokesman for the group, which works to battle corruption worldwide, said: "I don't think you could call it unfair on Nigeria and Afghanistan."
They added that the two nations "do want change".
Transparency International on Cameron's comments: "I don't think you can call it unfair on Nigeria & Afghanistan"
Transparency International:"not sure it's entirely helpful if you've invited people to your summit...but these countries do want to change."