Video report by ITV News journalist Mark McQuillan
The husband of prisoner Nazanin Zaghari-Ratcliffe said he hopes the visit of Foreign Office minister to Iran could hasten her release from her Tehran jail.
Andrew Murrison's visit to Iran on June 23 comes at a time of "increased regional tensions" as the US and Iran continue to trade barbs with one another.
Ms Zaghari-Ratcliffe has been held by Iranian authorities since April 2016 accused of spreading propaganda against Iran.
Her husband Richard Ratcliffe is on day eight of a hunger strike outside the Iranian embassy in London in support of his wife, who is also on hunger strike.
Speaking about Mr Murrison’s planned visit to Iran, Mr Ratcliffe said: “I’ve been asked how hopeful I am. I’m not sure if I’m hopeful, but certainly will be watching very closely to see how things develop and what comes back.”
He said: “It’s good that the minister’s going over there. It’s good that Iran and the UK are talking. It is good if they can find a way to solve this as quickly as possible.
“I obviously don’t plan on staying forever in front of the Iranian Embassy. The sooner a solution happens the better for our family and the better for both countries.”
Mr Ratcliffe added: “We are obviously looking for a quick resolution and that’s why she (Nazarin) went on hunger strike. It was to say enough’s enough.
“So we’re hopeful that it will lead somewhere.”
He said: “The more tension there is generally in the region the harder it is for a case like Naz to be solved and that’s true always.
“Certainly its a good thing the minister is going over to try and de-escalate but who knows how easy that will be to do?”
Mr Ratcliffe added: “Angry times make for difficult negotiations.”
Heightened tensions between the US and Iran are unlikely to make Ms Zaghari-Ratcliffe's release more realistic.
The trip was announced as Donald Trump said the US was "cocked and loaded" to retaliate against Iran for downing an American drone, but cancelled the strikes 10 minutes before they were to be carried out on Thursday after being told 150 people could die.
President Trump pulled out of a long-term deal struck with Iran in 2015 to limit its sensitive nuclear activities and allow in international inspectors in return for the lifting of economic sanctions.
The deal was signed by his predecessor Barack Obama along with the UK, France, China, Russia and Germany, which still support the agreement.
But Mr Trump declared it a ‘terrible’ deal and imposed more sanctions.
Tensions between the US and Iran have increased in recent weeks amid claims by Washington that Tehran has been behind attacks on oil tankers the Persian Gulf.
Announcing Dr Murrison’s visit, the FCO said: “The UK has an ongoing diplomatic dialogue with Iran.
“At this time of increased regional tensions and at a crucial period for the future of the nuclear deal, this visit is an opportunity for further open, frank and constructive engagement with the government of Iran.
“Dr Murrison will call for urgent de-escalation in the region and raise UK and international concerns about Iran’s regional conduct and its threat to cease complying with the nuclear deal to which the UK remains fully committed.”
Dr Murrison, a former naval officer and the MP for South West Wiltshire, was appointed Minister of State for the Middle East in May after Alistair Burt resigned the post in March over Brexit.