Rishi Sunak has challenged the Chinese premier, Li Qiang, over Chinese interference in the UK parliament, after two men were arrested amid allegations that a parliamentary researcher had spied for Beijing.

The prime minister met Li on the sidelines of the G20 summit in Delhi in an unplanned meeting hours after the Sunday Times revealed the researcher, who is understood to have had links to senior Conservative MPs, had been arrested along with another man.

After the meeting, Sunak said: “I obviously can’t comment on the specifics of an ongoing investigation but with regard to my meeting with Premier Li what I said very specifically is that I raised a range of different concerns that we have in areas of disagreement, and in particular, my very strong concerns about any interference in our parliamentary democracy, which is obviously unacceptable.