William Hague has stepped down as Foreign Secretary. ITV News understands he is likely to be replaced by Philip Hammond.
The reopening of the British embassy in Tehran is a startling development which represents a potential turnaround in our history with Iran.
The Foreign Secretary is today expected to announce plans to strengthen diplomatic ties with Iran.
The UK Foreign Secretary William Hague rejected a claim the government was "softening" its approach to Iran.
Speaking in the parliament, Mr Hague described the UK as "absolutely relentless" in its efforts to defeat terrorism around the world and added: "I can assure you that there is no softening of any of our policies in relation to Iran.
William Hague might have announced the reopening of the British embassy in Tehran today, but the Foreign Office is still advising people against traveling to the Middle Eastern country.
The Foreign Office currently advises "against all but essential travel" to most of the country, and "against all travel" to the eastern parts of Iran near the borders with Afghanistan and Pakistan.
People planning to travel to Iran should check the Foreign Office travel advice regularly and sign up for email alerts on the security situation, the spokesperson said.
The Secretary of State William Hague has issued a statement on the possible reopening of the British embassy in the Iranian capital, Tehran:
– William Hague
Our two primary concerns when considering whether to reopen our embassy in Tehran have been assurance that our staff would be safe and secure, and confidence that they would be able to carry out their functions without hindrance.
There are a range of practical issues that we will need to resolve first.
However it is our intention to reopen the Embassy in Tehran with a small initial presence as soon as these practical arrangements have been made.
William Hague has announced that Britain wants to reopen the British embassy in Iran as the West looks to normalise relations to help ease the crisis in neighbouring Iraq.
The Foreign Secretary told MPs that "circumstances are right" to re-open the British embassy in Tehran.
Mr Hague said he had discussed a number of matters in a meeting yesterday, including the situation in Iraq, with Iranian counterpart Mohammad Javad Zarif.
The UK has had no diplomatic presence in Tehran since a mob ransacked the British embassy in 2011.
Foreign Secretary William Hague has told ITV News the people of Iraq's second city of Mosul must be protected.
ITV News' News Editor Jonathan Wald reports:
UK Foreign Secretary #Hague tells ITV News the civilian population of Mosul must be protected,Iraqi leaders must form new government quickly
David Cameron said sexual violence has "no place as a weapon of war in this world" as a global summit on the issue opened its doors.
The Prime Minister said: "This Government will always seek to protect the most vulnerable in society, both at home and abroad.
"Both in the Modern Slavery Bill and in our campaign against sexual violence in conflict we are protecting victims and punishing perpetrators - with tougher sentences for traffickers and ending impunity for soldiers who commit rape."
"Britain should not and will not tolerate trafficking," he added.
Foreign Secretary William Hague, who is co-chairing the largest summit on sexual violence in conflict with Angelina Jolie, wrote on Twitter:
Angelina Jolie has said a summit on sexual violence in conflict must send a message around the world that there is "no disgrace" in being a survivor and that "the shame is on the aggressor".
The Oscar-winning actress dedicated the four-day London event to an unnamed and "abandoned" victim of rape in Bosnia.