Sir Keir met Chief Rabbi Sir Ephraim Mirvis and other members of the community at Kenton United Synagogue in north-west London on Thursday.
Before the meeting, Saul Taylor, the president of the United Synagogue, an umbrella group which includes the one visited by the prime minister, said there was a lot of anger in the Jewish community with the government.
“There’s been so much that’s been dragging,” he said, urging the government to proscribe Iran’s Islamic Revolutionary Guard Corps (IRGC).
“I don’t know what they’re waiting for.”
He said synagogues were spending enormous amounts of money on security guards, saying one spends £20,000 a month.
He called it a “tax on being Jewish in Britain”.
Sir Keir said “the use of proxies in this country is a growing concern and a real concern”, and the UK must “deal with malign state actors”.
“It’s very important this particular context, because I’m increasingly concerned that a number of countries are using proxies for attacks in this country.”
He said the government would bring forward legislation “as quickly as possible” to proscribe the IRGC. Other European countries have already done so.
Before the 2024 general election Labour had promised to proscribe it and has faced criticism that it has not yet happened. Other groups like the Iran-backed Hezbollah have been proscribed.
Last year, the government’s independent reviewer of terror legislation said new laws were needed to tackle state-run organisations.