An investigation by POLITICO revealed how parliamentary visits to foreign countries have been exploited by certain MPs and peers on All-Party Parliamentary Groups (APPGs) as an opportunity for the covert use of sex workers and for excessive drinking.

A Downing Street spokesman said Wednesday that U.K. Prime Minister Rishi Sunak was aware of the “concerning” reports, and urged lawmakers to focus on working for the public good.

“We’ve seen some of the reports over the Christmas period and just before, and some of the behavior reported is clearly very concerning,” the No. 10 spokesman said.

“The prime minister believes MPs should be working hard for the public, and the broad majority have focused on trying to solve our shared challenges, whether that be supporting the most vulnerable or working to make our schools better and our streets safer,” he added.

The spokesman declined to comment on whether the prime minister would support reform of APPGs — loosely-regulated groups of cross-party MPs, with interests in specific policy areas — saying this was a matter for the House of Commons authorities rather than the government.

Particular concerns have been raised over the activities of “country APPGs,” of which there are more than 130 operating within the U.K. parliament. These groups of MPs focus their investigative work on a specific foreign country or countries. Members frequently visit their country of interest for private fact-finding missions, funded by overseas governments or private companies and often on U.K. parliamentary time. Officials present say some MPs on such groups take such work seriously, but that others view the trips purely as a recreational pleasure.

Allegations reported by POLITICO included one former Conservative MP asking where he could find the nearest brothel during a visit to a country in southeast Asia, and a former minister staying on after official trips had ended to pursue his “interest in [local] women.”

A senior Labour MP displayed a fondness for “Russian girls” during trips overseas, according to a foreign diplomat, who said local officials felt powerless to intervene because they worried about preserving their influence in Westminster.

A separate article published Wednesday by the Times said British MPs on a visit to a dictatorship were greeted at their hotel by a number of sex workers. The Times said there was no suggestion the MPs knew in advance that sex workers would be present, or that they used their services.

On another visit to a country closely allied to the U.K., the Times reported, one MP had to be reprimanded for repeatedly propositioning young female interns who were helping to organize the tour.