Labour is demanding Boris Johnson closes a loophole that lets his ministers have secret meetings with lobbyists if they are hosted by foreign diplomats.
Deputy leader Angela Rayner is furious they do not have to declare who they see if they talk inside an embassy or high commission because the London buildings are technically foreign territory.
Ms Rayner said: "it's extraordinary meetings that would be under intense scrutiny if held in ministers' offices can be hidden from public view."
The loophole was uncovered after the Department for International Trade refused to disclose the identifies of attendees at an August 2019 dinner with Liz Truss.
The meal had been organised to discuss "issues relating to the UK-Australia relationship".
Labour ’s Deputy Leader added: "That would be bad enough in any circumstances, but it is clearly wrong now that the government is negotiating its own trade deals with foreign governments and granting preferential trade terms worth billions of pounds to overseas companies.
“Labour will immediately close this loophole and stamp out Tory sleaze by establishing an ethics and integrity commission that is independent from the Prime Minister and Downing Street.
"All Ministerial meetings with external organisations and individuals must be publicly disclosed, and there will be no exception for meetings hosted by foreign governments."
Shadow International Trade Secretary Emily Thornberry has written to the Prime Ministers ministerial code advisor Lord Geidt asking him to investigate.
She wants to know more about trade talks held at the Australian Commission.
Her Tory counterpart Liz Truss won't say what was discussed claiming exemption from rules.
