The biggest bus depot in the UK has been officially opened by the First Minister.

Nicola Sturgeon was given a tour of the headquarters of First Glasgow at its newly-constructed £20 million base in the south side of the city.

The depot houses 300 buses and 800 employees - although it has space for up to 450 vehicles and 1,200 workers.

Ms Sturgeon returned to the site almost exactly one year on from putting the first spade in the ground to start building work at the facility which contains a bus maintenance workshop, a dedicated deep-clean service tunnel and a specialist long-term vehicle repair unit.

Now fully operational, the depot has been officially named Caledonia.

Ms Sturgeon said: "First Glasgow is an excellent employer, setting an example for companies across the country.

"First Glasgow has a strong number of apprentices on board and is committed to helping people back to work, including long-term unemployed and ex-service personnel."

Fiona Kerr, managing director of First Glasgow, said: "This is the best and most advanced bus depot in the UK - as well as the biggest - and we see it as a launchpad for the growth and expansion of First Glasgow.

"Spending on new vehicles in 2015 will bring First Glasgow's investment in new buses, in less than three years, to above the £37 million mark.

"That, combined with this £20 million new facility, demonstrates an unrivalled financial commitment to Glasgow."