The British Museum’s director announced his resignation on Friday after admitting to mistakes in the inquiry into the theft of objects from its collection.

Hartwig Fischer, a German art scholar who has overseen the museum since 2016, said there may have been a better response to concerns that an employee was taking things, and that the failures “must ultimately” lay with him.

“It is evident that the British Museum did not respond as comprehensively as it should have,” he said in a statement.

The museum, one of London’s most popular tourist attractions, said last week a member of staff had been dismissed after items including gold jewellery and gems dating from the 15th century BC to the 19th century AD, had been found stolen from a storeroom.

Police said on Thursday said they had interviewed but not charged an unnamed man over the stolen artefacts.

The British Museum initially said in the statement that Fischer would step down “with immediate effect”, but later removed those words and said he would be resign once an interim leader had been found.

Fischer said that he withdrew remarks made about the art dealer who first alerted museum bosses to the stolen items. He expressed “sincere regret” over the “misjudged” comments.

Earlier this week, Fischer said Ittai Gradel, an antiquities dealer, withheld information about the scale of the stolen items when he contacted the museum.

The museum’s board of trustees, chaired by former British finance minister George Osborne, accepted Fischer’s resignation.

“We are going to fix what has gone wrong,” Osborne said. “The museum has a mission that lasts across generations. We will learn, restore confidence and deserve to be admired once again.”