UK's eavesdropping agency, Government Communications Headquarters (GCHQ) had reportedly snooped on the emails and telephone records of the foreign politicians and officials during the G20 summit in 2009.
According to Sky News, the officials' computers and phone calls were intercepted on UK government's orders of then prime minister Gordon Brown and the intelligence obtained was passed to ministers.
South Africa and Turkey, traditionally friendly countries, were among the countries targeted by the government for snooping.
Turkish Finance Minister, along with his members and Russian leader Dmitri Medvedev were among those targeted and their phone calls were listened to by the intelligence agency.
According to the report, the government's priority for the G20 summit included GCHQ to ensure that intelligence relevant to HMG's desired outcomes for its presidency of the G20 reaches customers at the right time and in a form which allows them to make full use of it.
After the summit, an internal report said that the call record activity pilot was successful and proved useful to note which nation was active before, during and after the summit.
NSA whistleblower Edward Snowden had revealed GCHQ using the US's spy programme to snoop on its citizens for taming potential terrorist threats.
However, GCHQ had earlier claimed that its work is in accordance with a strict legal and policy framework ensuring that their activities are authorized, necessary and proportionate, the report added.
