NI Secretary Theresa Villiers defends G8 security cost
Northern Ireland Secretary Theresa Villiers has defended the cost of security for the G8 conference in County Fermanagh as "money well spent".
There have been two arrests so far - one in Belfast and one in Enniskillen, the venue for the summit.
Security has cost at least £50m, with thousands of police on duty, but the final bill is expected to be higher by the time the global leaders leave.
Mrs Villiers praised the work of the police in keeping the summit "secure".
The two-day summit at the Lough Erne Resort finishes later.
Security chiefs said they had not anticipated any significant public disorder. However, there is a threat from dissident Irish republicans opposed to the Northern Ireland peace process.
"All the money spent on security has been money well spent. The terrorist threat continues to be severe," Mrs Villiers said.
"We can all imagine dissident republicans would have loved to have staged an attack when the world's media is in Northern Ireland.
"The fact they have been unable to do that is a tribute to work done by the PSNI (Police Service of Northern Ireland) to ensure a safe and secure summit."
She added: "If that kind of preparation had not been done and a terrorist attack had taken place, the impact would have been catastrophic.
"You have to plan for the worst. Without that excellent preparation we probably would have been seeing more public order issues than we have so far."
Details of the total security bill would be published after the summit, she said.
"But I am absolutely convinced this summit will generate very significant benefits for Northern Ireland," Mrs Villiers said.
"It is tremendous to show the world what a beautiful place Northern Ireland is. The backdrop at Lough Erne is absolutely stunning.
"If 99.9% of the world's population think of Northern Ireland at all, they probably think of riots in east Belfast and burning cars. It seems to be the only time Northern Ireland is in the news.
"Now we have Northern Ireland in the news for a good reason. That is the kind of publicity money can't buy."
About 8,000 police have been on duty and road checks set up near airports and the G8 venue as part of the security measures.
Northern Ireland First Minister Peter Robinson said police were in a no-win position over security costs, most of which would be met by the UK government.
"If they had a lesser level of security and something was to happen, people would be asking: 'Why was there not enough police on the ground and more of an effort made?'," he said.
"I think they've got it right. It is far better to be over-prepared than to have some event occurring and regretting to take those steps.
"Yes, there is a high cost for a very short period of time, but there is a tremendous economic advantage for Northern Ireland."
Deputy First Minister Martin McGuinness said there had been a lot of conflict around previous summits. Even though advance G8 teams had to prepare for the worst, he predicted this would be one of the most peaceful ever held.
"The worst has not transpired. We are not yet over this, but we are hugely optimistic things will be peaceful," he said.
"How could you pay for this publicity? There are places throughout the world that would dearly love to have the opportunity we have been presented with over these couple of days," he added.