Iran’s envoy to Britain said on November 17 that Britain plans to transfer more than 400 million pounds ($527 million) soon to settle a debt from the 1970s.

Ambassador Hamid Baeedinejad made the announcement in a statement posted to his Telegram social-media account, saying there was no link between the debt payment and the issue of an Iranian-British aid worker who has been jailed by authorities in Tehran.

Britain owes the funds to Iran as a result of a disputed arms deal during the 1970s and has sought legal advice about whether it could transfer the money to Iran.

Britain’s Telegraph newspaper reported on November 15 that the British government is preparing to transfer the funds to Iran as it seeks the release of a jailed Iranian-British aid worker.

The Telegraph report, citing unidentified British government sources and diplomats, said Britain did not want to directly link the payment to the release of jailed charity worker Nazanin Zaghari-Ratcliffe.

But the sources said Britain is seeking to secure the “goodwill” of Tehran in the midst of an effort to win Zaghari-Ratcliffe’s release.

British Foreign Secretary Boris Johnson has vowed to do “everything” he can to release Zaghari-Ratcliffe, who was detained in Tehran in April 2016 and sentenced to five years in prison on charges of plotting to overthrow Iran’s clerical establishment.

Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, denies the charges.

Arrests during 2015 and 2016 of Iranians with dual citizenship in Western countries, including Zaghari-Ratcliffe, were seen as a bid by the Islamic Revolutionary Guards Corps (IRGC) to undermine Iranian President Hassan Rohani and the process of improving relations with the West.

Based on reporting by The Telegraph, Reuters, and the BBC