The Foreign Secretary instructed the FCDO to summon Iran's most senior diplomat after Iran carried out the first execution of a protestor since demonstrations began in September.
Foreign Secretary James Cleverly said:
The execution of Mohsen Shekari by the Iranian regime is abhorrent. He is a tragic victim of a legal system in which disproportionate sentences, politically motivated trials and forced confessions are rife.
We have made our views clear to the Iranian authorities - Iran must immediately halt executions and end the violence against its own people.
Vijay Rangarajan, Director General for the Middle East, held the meeting with Mehdi Hosseini Matin to underline that in the UK's view this is a grossly disproportionate action, which is designed to intimidate ordinary Iranians and stifle voices of dissent.
He stressed that the UK opposes the death penalty in all circumstances and urged Iran to immediately halt executions and the imposition of death sentences.