Prime Minister Manmohan Singh [Images], who is in Gleneagles for the G8 summit of industrialised nations, is unlikely to have a bilateral meeting with Tony Blair [Images] as the British Prime Minister is going back to London [Images] after a series of explosions ripped through the capital city.

"The bilateral meeting with Blair has been postponed. It is quite likely that the meeting might not be held on Thursday or even be cancelled," an Indian external affairs ministry official said.

• Multiple blasts rock London

Singh, invited as an observer to the summit, is expected to have bilateral meetings with Russian President Vladimir Putin [Images] and French President Jacques Chirac.

Security concerns and the need to step up cooperation to counter terrorism are likely to figure in these talks, apart from the issue of reform of United Nations and efforts of G4 countries -- India, Germany [Images], Brazil [Images] and Japan [Images] --  for permanent membership of the Security Council.

The G-8 summit discussions are expected to focus mainly on climate change and sustainable development, issues of contemporary and pressing importance.