Exclusive: Foreign secretary to make visit in bid to win release of jailed dual national and to put UK-Iranian relations on new footing

Boris Johnson will travel to Tehran this weekend in an effort to win the release of the British-Iranian woman Nazanin Zaghari-Ratcliffe, who has been held in a Tehran jail for nearly two years.

Making his first visit to Tehran as foreign secretary, Johnson will also seek to put UK-Iranian relations on a new footing, pointing to Britain’s strong defence of the Iranian nuclear deal signed in 2015.

Johnson has played down expectations of an immediate breakthrough in the case of Zaghari-Ratcliffe. Progress may depend on his conversations in two days of talks with senior Iranian figures including the foreign minister, Javad Zarif.

The UK will be presenting ideas about how British banks, with the help of the Bank of England, can operate across Iran with less fear of being subject to mainly US-imposed sanctions and fines. Iran believes the nuclear deal has not led to the flourishing of trade or the interconnection with the western banking system it had been promised.

Play Video 0:35 Boris Johnson: 'I apologise to Nazanin Zaghari-Ratcliffe and her family' – video

Zaghari-Ratcliffe, said to be close to a mental breakdown, had been due to make a fresh appearance in court on Sunday facing new charges relating to espionage that could result in her five-year sentence extended by as much as 10 years. It is not clear if the hearing will still go ahead while the foreign secretary is still in Tehranand there have been suggestions it may be delayed.

In a sign that an immediate breakthrough is not imminent, Johnson said on Thursday her case was extremely difficult. Iran does not recognise dual national status so the UK has a problem at the outset lobbying on her behalf.

Hopes for her early release grew last week when it was revealed that an Iranian government health commissioner was to make checks on her health. It has been claimed she has been suffering panic attacks, insomnia, bouts of depression and suicidal thoughts.

She was arrested at Tehran airport two years ago with her daughter who has stayed in the Iranian capital with her grandmother.

Johnson has insisted the second set of charges laid against her are not related to his errorlast month in telling the foreign affairs select committee that she had been in Iran to train journalists.

The possible coincidence of his visit and her reappearance in court had not been planned since details of his visit were agreed between the two sides before the date of her new court appearance had been set. The additional evidence is supposed to include a BBC pay stub and an email dating from 2010 saying that she had trained journalists in Iran.

After some delay, Johnson met Richard, the husband of Zaghari-Ratcliffe, and apologised if his remarks in parliament could have been construed by the Iranian judiciary as a sign that she had been in Tehran on anything other than her holiday.

Johnson said he had meant to say the worst offence of which she had been accused by the Iranian government was training journalists, not that he personally knew she had been offering this training.

The separation between the Iranian diplomatic service and the more politicised state courts makes the task of influencing the regime’s thinking more complex.

Although Johnson said on Thursday that what Iran was doing in the region was entirely separate to consular cases, the possibility of her release is inevitably interwoven with broader British-Iranian relations.

Johnson has been a strong defender of the Iranian nuclear deal signed in 2015, personally travelling to Washington to urge US Republican congressmen not to follow Donald Trump’s lead and abandon the deal. No independent body has found any breach by Iranand the UK insists the deal is ringfenced from any wider criticism of Iran’s ballistic missile programme or its wider behaviour in Syria, Yemen and Lebanon.

At a press conference on Thursday, Johnson said he would be raising with the Iranians “the supply of rockets to Hezbollah in Lebanon and helping the Houthis to launch missiles against Riyadh. This is causing fear. This is causing terror in parts of the Middle East. This is disruptive and dangerous behaviour. That is the message I will be taking”.

Iran will want to hear British ideas to ease banking restrictions imposed largely due to US sanctions.

Britain can still help Nazanin Zaghari-Ratcliffe – if Boris Johnson does his job | Malcolm Rifkind Read more

Most UK banks fear they will face swingeing fines by US federal authorities if it emerges they funded a commercial deal between firms and an Iranian entity banned under US sanctions, such as the Iranian Revolutionary Guard Corps. Ownership laws in Tehran are opaque, and determining whether an IRGC firm has only a minority stake in a company is hard. There has been discussion of whether the Bank of England could indemnify some deals, but the risk to the UK taxpayer, and the level of commitment to the Bank may prove too large.

The impasse has even left the Iranian embassy in the UK unable to set up a bank account in this country and the five major Iranian banks in the UK struggle to operate.

Iran’s outstanding other claim is for £400m in compensation for the non-delivery of Chieftain tanks ordered by Tehran in the 1970s. The level of the compensation is largely settled, following a lengthy court case that the Iranians essentially won. The UK had made a payment into court, but unresolved issues over the method of payment, possibly using the Bank of England, and the lawfulness of payments to the Iranian ministry of defence remain obstacles. It is also possible the Iranians are seeking interest on the money that should have been paid to them.