More than £90m is being invested in 160 new electric buses, creating "smoother, quieter and greener journeys".

The new fleet will operate across Bristol, Somerset and Wiltshire by next summer as part of First Bus' mission to cut its emissions over the next ten years.

Depots will also be electrified at Bath's Weston Island and Lawrence Hill in Bristol during the project, which is jointly funded by First Bus and the government.

Doug Claringbold, managing director for First Bus in the West, said: "We're now a year away from nearly half our fleet being electric and nearly all our depots being electrified – that's a phenomenal achievement."

The investment brings the region's total number of electric buses to 258, First Bus said.  They will serve 750,000 passengers per week on 37 services.

About £59m has already been invested in electrifying 98 buses and two depots at Hengrove in Bristol and Weston-super-Mare.

"Last month there was a real buzz among our teams, customers and stakeholders when we officially unveiled our electrified depot at Weston-super-Mare and passengers took their first journeys on our electric buses, and I cannot wait for even more of our region to go electric," Mr Claringbold said.  "To be more than doubling the number of electric vehicles, transforming four out of five of our depots and ensuring three quarters of a million customers a week can travel electric shows a real commitment to making bus travel smoother, quieter and greener for our region."

First Bus invested nearly £70m in the project, with a further £20m government funding from the latest round of the Department for Transport's Zero Emission Bus Regional Area scheme.