But the terms of the deal, which roll back a number of key pledges from the anti-austerity government, have split the ruling party. Mr Tsipras failed to get the backing of at least 120 of his own MPs, a constitutional threshold that could oblige him to trigger a vote in his leadership.
In a detailed evisceration of the austerity measures, former rebel finance minister Yanis Varoufakis denounced the agreement as encapsulating “the Greek government’s humiliating capitulation”.
“Greek sovereignty is being forfeited wholesale” he said. “Not since the Soviet Union has wishful thinking, unsupported by anything tangible, posed as policymaking.”
Support for the ruling coalition has becoming vanishingly thin. Greece’s two main opposition parties – which have so far voted to keep the country in the euro – vowed to pull the plug on the embattled premier should a vote be called in the coming weeks.
Pasok, the much depleted socialist opposition, joined the conservative New Democracy in refusing to endorse Mr Tsipras and his junior coalition partner, led by defence minister Panos Kammenos.
“The government has signed the third and most onerous bail-out. All the negative consequences for the country and its citizens bear the signatures of Mr Tsipras and Mr Kammenos,” said a Pasok party statement.
“We have no confidence in the Tsipras-Kammenos government and of course will not give it if we are asked.”
Should he fail to win majority backing from Greece’s 300 MPs, Mr Tsipras is almost certain to hold a snap election.
Syriza’s radical Left Platform – which makes up a third of the party’s membership – has already threatened to form a breakaway faction under the leadership of firebrand former minister Panagiotis Lafazanis. Grassroots party members are set to hold an internal ballot over the party’s position in September with talks that an election could be called for as early