The graffiti above a portrait of Britain's queen provided a scrawled reminder of just how venomous Anglo-Iranian relations once were.
"Death to England", read the message in orange marker pen, daubed inside the elegant ambassador's residence of the British Embassy in Tehran.
The motif was still visible yesterday when Britain's foreign secretary Philip Hammond officially reopened the mission, four years after a mob had vandalised its spacious premises.
On November 29 2011, the building, along with every other in the embassy's five-acre compound, was sacked by about 200 people, including members of the regime's Basij militia.
During the assault, a protester daubed his slogan above the queen's portrait. The same phrase also appears in three other places.
Britain has spent hundreds of thousands of pounds on restoring the embassy, without receiving any compensation so far from Iran.
Paying the first visit to Iran by a foreign secretary since 2003, Mr Hammond voiced optimism about future ties between Britain and the Islamic Republic.
Asked why the graffiti had not been cleaned away before the ceremony, Mr Hammond replied: "There is an ongoing programme of work."
British officials point out that the embassy consists of thousands of square feet of floor and wallspace, much of it vandalised in 2011, and almost all of it has been cleaned up. The ambassador's residence has been painstakingly restored.
But the building is of such historic value that only a specialist can clear the graffiti without causing more damage - and none had solved the problem in time for yesterday's ceremony.
Mr Hammond explained why Britain had not insisted on Iran's paying compensation before the diplomatic mission was reopened.
"My experience is that when you set down lists of preconditions in an environment where you don't have channels of dialogue, all that will happen is stasis," he said.
"The right thing to do is to move forward one step at a time, to reopen the embassy to re-establish dialogue."
He stressed that Britain was still expecting to be compensated, but this issue would not be allowed to stand in the way of improving relations with Iran.
"Yes, of course we will want to pursue a proper claim for the damage that was done to this compound, but actually the most important thing now is to look to the future and rebuild our relationship," he said.
"If you think over the medium term, the size and importance of Iran in the region, the scale of its economy, the significance of the opportunities that will become available to British business and British investment - these are the big wins for both sides from building the relationship."
Mr Hammond was accompanied to Tehran by a British business delegation with interests in finance and oil.
Key to the warming of ties - which has also seen Iran reopen its embassy in London - was the announcement of the nuclear agreement in Vienna last month.
There were conciliatory moments yesterday. Mohammad Javad Zarif, the Iranian foreign minister, drew a distinction between America and Britain.
"If we are going to have a bigger relationship with the EU, this means having a bigger relationship with Britain," he said. (© Daily Telegraph, London)