Alexis Tsipras, the Greek prime minister, was flying to Brussels on Wednesday morning in a last-ditch effort to salvage a bailout deal amid growing signs his compromise offer was facing calls by creditors for significant revisions. However, in a sign of optimism that a deal might be done, a Greek central bank official said that about €100m returned to the country’s banking system on Tuesday and so no request was made to the European Central Bank on Wednesday to extend the limit of its emergency liquidity assistance (ELA) to the sector.