An influential group of MPs has urged the Prime Minister to boycott a Commonwealth summit in Sri Lanka over human rights abuses.
The Foreign Affairs Committee said the decision to hold the Heads of Government Meeting in Colombo next year was "wrong".
The call came in a report on the future of the Commonwealth, which delivered a wider warning that the network's moral authority was being "undermined by the repressive actions of member governments".
The MPs said they were "disturbed" by the ineffectiveness of the mechanisms for upholding the Commonwealth's values, and backed a push to codify them in a charter.
The body's secretariat needs to "sharpen, strengthen and promote its diplomatic performance", according to the report.