On board Air India One, Sep 7 (IANS): With no permanent friends or foes in politics, a re-alliance with Mamata Banerjee's Trinamool Congress (TMC) is always open, Prime Minister Manmohan Singh said Saturday.

"In politics there are no permanent enemies and permanent friends. And in many ways, a week in politics is sometimes an unusually long period of time," Manmohan Singh said on his return from the G20 summit in St. Petersburg.

"So I don't rule out alliances," he added, terming Banerjee a respectable member of the Congress party at one time and now a leader of the Trinamool Congress.

"We would very much like like-minded, secular-minded persons should work again to give our country's polity a thrust in favour of secular elements."

The Trinamool Congress had parted ways with UPA (United Progressive Alliance) government on September 21, 2012 on a spate of policy issues ranging from allowing foreign investment in multi-brand retail, increase in diesel prices and putting a cap on subisidised LPG (liquefied petroleum gas) cylinders.