UK-Iranian ties are thawing as former British Foreign Secretary Jack Straw leads a delegation of members of parliament to Tehran.
... this visit is very important .... Jack Straw has been regarded by many as a ... British politician, who has always looked warmly towards Iranians unlike many other ... western leaders, who have always looked at Iran with contempt and animosity.
They are meeting Iranian Foreign Minister Mohammad Javad Zarif as well as other senior members of parliament.
The visit is the first since Britain severed almost all ties with the Islamic Republic after its embassy was attacked in November 2011.
And though both countries' embassies remained closed in London and Tehran, relations between them have improved since Hassan Rouhani took over as president last year.
Relations between Britain and Iran deteriorated during former president Mahmoud Ahmedinijad's time in office.
In November 2011, the UK imposed new sanctions against Iran, worsening an already weak economy. Iran responded by downgrading its relations with Britain - and the UK embassy in Tehran was then attacked.
British Foreign Secretary William Hague warned Iran would face 'serious consequences' over the incident, and Britain expelled Iranian diplomats and closed its embassy in Tehran.
It was only in October last year that both countries announced they would appoint diplomats to work towards restoring relations.
This is not the first time that Britain has restored relations with countries it once considered 'rogue nations'.
This is a move in the right direction but these are giants in politics ... they don't represent anything from the business community.
In 2004, Tony Blair shook hands with Muammar Gaddafi saying there was real hope for what he called a 'new relationship'. The historic move came after Libya accepted responsibility for the bombing of the Panam flight over Lockerbie that killed 270 people in 1988.
And in 2012, British Prime Minister David Cameron became the first western leader in five decades to visit Myanmar - a country once considered a pariah state.
He announced a dramatic shift after opposition leader Aung San Suu Kyi was elected to Parliament and called on the EU to ease sanctions on Myanmar.
So, do these visits have more to do with business opportunities than politics?
Inside Story with presenter Hazem Sika, discusses with guests: Sadegh Zibakalam, professor of political science at the University of Tehran; Babak Emamian, a member of the British-Iranian Business Association; and Richard Dalton, a former British ambassador to Iran.
"This is going to be a slow process, each country has got its concerns about the policy and behaviour of the other, and there will be a discussion going on between the two governments. Mr Straw and his delegation are not part of those discussions, this is a parallel activity ....
"This is an important visit, it is a symbol of what the British government wants which is a renewed, creative, cooperative relationship with Iran, not glossing over the serious differences that we have on policy but seeking to work together where we can in our mutual interests, and in the interest of the Middle East region as a whole."
Richard Dalton, a former British ambassador to Iran