LORD Smith of Kelvin, the Scots chairman of the UK Government's flagship Green Investment Bank (GiB), has come under fire after it emerged he earns more than £2300 a day in his part-time role.

The 68-year-old executive, one of Scotland's leading business figures, is paid £120,000 a year to work one day a week at the publicly owned Edinburgh-based GiB, set up to invest in environmentally sustainable projects.

It is thought to be the highest per-day basic salary in the public sector outside of the bailed-out banks.

Full details of his remuneration emerged as the bank made what it said was an expected net loss before tax of £6.2m in its first 10-and-half months.

Robert Oxley of campaign group TaxpayerScotland criticised the salary, saying: "Lord Smith of Kelvin is pocketing a frankly astonishing amount of taxpayers' money for just one day's work. The Green Investment Bank is a gimmick that doesn't deliver."

Lord Smith's remuneration in other posts includes £250,498 as chairman of Weir Group for 2012, £353,000 as Scottish and Southern Energy chairman for 2013 and about £83,000 as director of South Africa-based Standard Bank.

Last month, Lord Smith, who chairs the organising committee for the Glasgow 2014 Commonwealth Games, was appointed the Chancellor of Strathclyde University.

A spokeswoman for the UK Department of Business, Innovation and Skills defended the remuneration, saying: "Lord Smith of Kelvin's pay level is below comparable roles in the private sector. One of our key objectives in creating the GiB has been to recruit and retain a top-class team with the requisite experience and skills to run this groundbreaking institution successfully."

A spokesman for Lord Smith said: "There is a wider context here. Lord Smith has done some very significant jobs. He chooses to remain in Scotland and was instrumental in bringing the GiB to Scotland. The wider contribution Lord Smith makes to Glasgow and Scotland is significant. Frankly, Scotland needs more people like Robert Smith."