The "circumstances were right" to take this "important step forward" according to Hague, reports BBC. The minister was referring to the negotiations with world powers over Iran's nuclear program, which are nearing a July 20 deadline.
"There has never been any doubt in my mind that we should have an embassy in Tehran if the circumstances allowed," Hague said. "Iran is an important country in a volatile region, and maintaining embassies around the world, even under difficult conditions, is a central pillar of the UK's global diplomatic approach."
Hague denied arguments by British Members of Parliament (MPs) that the move was "soft" in the face of the Islamic regime's nuclear program, claiming "I can assure you that there is no softening of any of our policies in relation to Iran."
The British foreign minister said Iran must "cease support for sectarian groups across the Middle East and reach a successful conclusion to nuclear negotiations."
Many have highlighted the danger of the negotiations leading to a nuclear armed Iran; it has been argued that with its 19,000 centrifuges, Iran can maintain a sudden breakout capability of six to seven weeks in the event of a bad nuclear deal, meaning that it can quickly achieve nuclear weapons if not totally stripped of enrichment capability.
Iran threatened last Thursday it would resume uranium enrichment activities if no agreement is reached with the West. Under the interim deal reached last November, Iran committed to limit its uranium enrichment to five percent and is gradually winning access to $4.2 billion of its oil revenues frozen abroad and some other sanctions relief.
However, a UN report in May revealed Iran is bypassing the sanctions, which were meant as an economic incentive to force the Islamic regime to abandon its nuclear program.
If the embassy is re-opened, the UK would not be the only western country seen as "softening" its stance. Iranian Supreme Leader Ayatollah Ali Khamenei claimed last Wednesday that US President Barack Obama's administration has "renounced the idea of any military actions" against Iran.
Last month Khamenei said that Western expectations for the Islamic Republic to limit its missile program were "stupid and idiotic". In the past, he has declared that Tehran will never give up its nuclear program. He also revealed in January that the nuclear talks are merely a tactic to stall for time.
Obama's warnings in March that the military option is still on the table regarding Iran's nuclear program were called "the joke of the year" by Iran's military.