World powers and Iran have formally announced a comprehensive nuclear accord.
Federica Mogherini, the European Union's foreign policy chief, said: "Today is an historic day."
She added that it was a great honour "for us to announce that we have reached an agreement on the Iranian nuclear issue".
"The world can be reassured all Iranian routes to the nuclear bomb have been closed off," according to the foreign secretary Philip Hammond.
The UK also plans to re-open an embassy in Iran once confidence in its nuclear ambitions has been restored.
As part of the deal, global economic sanctions on Iran are also set to be relaxed in stages.
Prime minister Netanyahu has likened the nuclear deal with Iran to the unsuccessful 1994 deal on North Korea's nuclear programme.
An end to Iranian nuclear question could soon be a reality after years of hard and often tense negotiations.