Foreign Secretary William Hague has hailed the nuclear agreement between Western powers and Iran as “good for the whole world”.
An interim deal to restrict Iran’s nuclear programme was reached after five days of talks in Geneva.
Writing on Twitter, Mr Hague said it was an “important and encouraging first-stage agreement with Iran”.
Iran has agreed to curb some of its nuclear activities in return for about £4.3bn ($7bn) in sanctions relief.
“This is an important moment, an encouraging moment, in our relations with Iran and in our efforts to prevent nuclear proliferation in the world,” Mr Hague told journalists.
The deal would mean that Iran’s nuclear programme “won’t be able to go forward over the next six months, over the six months of this agreement, and in some respects will be rolled back”, Mr Hague continued.
“And that, we hope, will give us the opportunity to negotiate a comprehensive and final settlement of these issues.
Negotiations were painstaking. Tomorrow hard work begins of implementing and building on the agreement”
UK foreign secretary
“It is necessary and in the interests of the world for there to be an international agreement, about Iran’s nuclear programme, that can lead then to a comprehensive settlement to us all being assured that that programme is exclusively for peaceful purposes.”
On Twitter, the foreign secretary added: “This agreement shows it is possible to work with Iran, and through diplomacy address intractable problems.
“Tonight’s agreement with Iran [is] good for the whole world, including Middle Eastern countries and the people of Iran themselves.
“Negotiations were painstaking. Tomorrow hard work begins of implementing and building on the agreement.”
The EU’s foreign policy chief Baroness Ashton said: “Of course, when you get to the detail of trying to finalise the agreement, in a sense that is the hardest part.
“But we’ve done it in a spirit of cooperation, good atmosphere, and although it has been intensive, and very, very detailed, it has also been done with a real sense of mutual respect.
“I’m delighted that we’ve got there.”
US President Barack Obama has also welcomed the deal, saying it included “substantial limitations which will help prevent Iran from building a nuclear weapon”.
Iran agreed to give better access to inspectors and halt some of its work on uranium enrichment.
President Hassan Rouhani said the deal recognised Iran’s nuclear “rights”.