Campaigners fighting for the release of a British-Iranian woman held in jail in Iran are due to protest outside the Iranian Embassy in London.
The husband of Nazanin Zaghari-Ratcliffe will deliver letters of solidarity and a petition from over 100,000 Amnesty supporters to the country's deputy foreign minister as he visits the UK on Wednesday.
Richard Ratcliffe says he will ask the ministerial delegation to take them back to Iran for his wife.
The letters were sent to Evin Prison in the islamic country but were returned.
Nazanin Zaghari-Ratcliffe was arrested in April 2016 at an airport in Tehran after a family holiday.
A charity worker with the Thomson Reuters Foundation, she is serving a five-year sentence after being convicted on what campaigners say are unspecified national security charges.
She has suffered a serious decline in her physical and mental health since being jailed.
Her husband is also seeking a personal meeting with the deputy foreign minister during his visit to push his wife's case.