She was sentenced to ten years in jail the following year.
In a statement, the British Council said: “We have always refuted the original charges made against Aras.
“We are very proud of her work in our London office as an arts programme officer supporting a greater understanding and appreciation of Iranian culture in the UK.
“This was important work which reflects the value of cross-border cultural collaboration.”
The government spokesperson also claimed she confessed to working with British intelligence.
Speaking from Tehran, her lawyer Hojjat Kermani confirmed her acquittal to the Associated Press saying her conviction had been “against Shariah”.
Mr Kermani said she flew out of Tehran on Monday but had been free in recent months as she appealed a travel ban.
During her sentence, Ms Amiri had been held in the same section of the infamous Evin prison as Nazanin Zaghari Ratcliffe.