* New finance minister unlikely to take softer line
* Expected to pursue issue of debt relief for Greece
* Believes Greece has been unnecessarily impoverished
By Lefteris Karagiannopoulos
ATHENS, July 6 (Reuters) - Euclid Tsakalotos, the mild-tempered professor who was appointed as Greece's new finance minister on Monday, is a clear change in style from his combative predecessor Yanis Varoufakis.
The 55-year-old Tsakalotos studied at prestigious private London school St Paul's and at Oxford University, speaks Greek with a British accent and rarely appears in public, let alone wearing the torso-hugging T-shirts Varoufakis favours.
But if European officials expect Athens' new finance chief, who has already been a key negotiator in drawn-out talks between the Greek government and creditors, to take a softer approach in the substance of new bailout talks, they can think again.
As the brainchild of Syriza's economic thinking, Tsakalotos is likely to redouble efforts to put one of the most contentious issues in the five months of negotiations between Greece and its creditors -- debt relief -- back on the table.
Tsakalotos, who co-authored a book with Greek central bank governor Yannis Stournaras, has been dubbed in leftist jargon a "Revolutionary Europeanist" -- an economist who supports European Union integration, but not its capitalist principles.
Like Varoufakis, Tsakalotos has often decried Europe for big democratic deficiencies and argued that ill-guided fiscal austerity imposed by the core of the euro zone has unnecessarily impoverished Greece and other countries on the periphery.
"European Monetary Union has created a split between core and periphery, and relations between the two are hierarchical and discriminatory," he wrote in a paper on the website of the Alliance for Workers' Liberty, a British socialist group.
Born in Rotterdam in the Netherlands, Tsakalotos has a notable international academic curriculum. He studied politics, philosophy and economics as an undergraduate at Oxford, where he later completed his PhD in economics in 1989. He taught at the University of Kent before returning to Athens as a professor at Athens University of Economics.
There, nearly a decade ago, he led his students in a months-long protest against a proposed reform of Greece's education system.
When students occupied classrooms and marched through the streets, Tsakalotos was on the frontlines, recalls Thanos Tsouknidas a 30-year-old accountant who knew him from the time.
"He was there, involved in the struggle. We were fighting together," recalls Tsouknidas.
"He is a pure left-wing individual and professor. His door was always open to all students, to discuss university issues or political issues, or for a normal chat."
The active role of Tsakalotos, who joined the teachers' union, brought him popularity. Classes, including a course in the history of economic theory, were packed, recalls Vassilis Alevromitis, 25, a former student who is now unemployed. Some students would giggle at the professor's British accent.
Tsakalotos dabbled in politics in the teachers' union, drawing close to Syriza, which was growing in popularity on the back of Greece's economic crisis.
He was first elected to parliament in May 2012, and re-elected in January 2015, when his party swept to power and Alexis Tsipras to the premiership.
Tsakalotos has pushed Tsipras to ally with other European left-wing groups, including Podemos in Spain and Ireland's Sinn Fein. In March, the economist visited Dublin and addressed Sinn Fein political delegates, alongside leader Gerry Adams.
Tsakalotos has said debt relief for Greece could happen in many forms. In an interview with Reuters, the economist suggested Athens be offered debt relief in the form of having the European bailout fund - known as the European Stability Mechanism - take over Greek bonds held by the ECB - as one option that would not increase debt for Greece or its partners.
"There are lots of technical solutions on how that could be done," he said. "If there is goodwill, I can think of 10-15 solutions right now of how that could be done. If there's no political goodwill then for any solution I can think of a drawback."
People who know Tsakalotos say he has strong negotiating qualities, which will come in handy as Athens heads back into talks with creditors.
"He is the ideal person to help the Greek government break the current deadlock and reach an agreement with international lenders. He is modest, calm, and a very good listener," says Panicos Demetriades, a former ECB Governing Council member for Cyprus who knew Tsakalotos in Britain. (Additional Reporting by Michele Kambas; Writing by Alessandra Galloni; Editing by Giles Elgood)