THE driver of a bin lorry which careered out of control in Glasgow killing six people is "getting better", but remains on sick leave - ahead of a preliminary inquiry into the tragedy which begins tomorrow.

Harry Clarke, 58, collapsed at the wheel of the 32-tonne truck, which mounted the pavement and ploughed into Christmas shoppers on December 22.

Today's (mon) preliminary hearing comes ahead of a fatal accident inquiry (FAI), which begins on July 22 at Glasgow Sheriff Court.

In February, Clarke said he had fallen unconscious at the wheel and could not remember anything about the crash.

The Crown Office later concluded that the driver and his employer, Glasgow City Council, would not face criminal charges.

A statement said: "Despite its catastrophic consequences there is no evidence to suggest that the driver's conduct at the time amounted to a breach of the criminal law."

Clarke is expected to be represented at the FAI by a legal team appointed by his trade union, Unite.

A source at the union said: "At this stage he's been dealing with lawyers. The union has assisted him and he's under the legal auspices of the union. He's a member and the help is offered to any member. There are no charges, which makes things clearer for him. My driver was involved in a terrible accident."

Clarke was treated at Glasgow Royal Infirmary for two weeks before he was discharged on January 5.

The source at Unite added: "He's getting better, he's feeling a bit better, but he's still off sick, obviously, and he's still feeling the effects of the tragedy."

Scotland's second most senior law officer, Solicitor General Lesley Thomson, is to lead Crown evidence at the inquiry. The FAI will be held before Sheriff Principal Craig Scott QC.

A spokesman for the Crown Office said: "The Crown Office can confirm that the Solicitor General, Lesley Thomson QC, will be conducting the fatal accident inquiry (FAI) into the road traffic incident which resulted in the deaths of six people in Glasgow City Centre on December 22, 2014."

Student Erin McQuade, 18, and her grandparents Lorraine, 69, and Jack Sweeney, 68, from Dumbarton, teacher Stephenie Tait, 29, from Glasgow, tax worker Jacqueline Morton, 51, from Glasgow and 52-year-old Gillian Ewing, from Edinburgh, lost their lives in the tragedy.

Ten others were injured when the runaway refuse truck careered along Queen Street before crashing into the Millennium Hotel.

Speaking publicly for the first time at the beginning of February, Clarke said: "I understand a lot of people want to know what happened that day. I wish I could tell you but I can't. I never had anything wrong with my heart until that day."