FIRST Minister Nicola Sturgeon has officially opened the biggest bus depot in the UK.

She toured the new headquarters of First Glasgow which has moved to its newly built £20million base on Cathcart Road.

It houses 300 buses and 800 staff but has space for up to 450 buses and 1200 employees allowing the business to grow.

What was vacant ground is now home to a bus maintenance workshop, a deep clean service tunnel and a vehicle repair unit.

The depot, which has been named Caledonia by staff after a competition, is one of the greenest in the country, incorporating enough solar panelling to power 40 homes a year and harvesting rainwater to be used in vehicle washes.

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

"It 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."

First Glasgow managing director Fiona Kerr said the depot was the best and most advanced in the UK as well as being the biggest.

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

"That combined with the £20m new facility demonstrates an unrivalled financial commitment to Glasgow.

"We are committed to delivering the best services for our customers and providing the best operating environment for our staff.

"This new centre of operations will help us improve upon our strong punctuality and reliability performance as we strive to be the best bus company in the UK and encourage people in our communities to consider bus travel more often."

City council leader Gordon Matheson said he was delighted the city was home to the biggest and most eco-friendly bus depot in the UK.