Some 2,400 homes remain without power in Voe, Brae, Yell and the West Mainland - with engineers warning power may not be restored to some properties until the weekend.

Scottish and Southern Electricity Networks (SSEN) Distribution said it was continuing to "battle prolonged severe weather conditions".

A team of 125 people is carrying out repairs to restore power, with SSEN saying "this remains likely to extend to the end of this week".

"Depending on weather conditions and travel availability, it is possible this could extend into the weekend for some properties," it added.

Helicopters were sent to survey overhead power lines, with some circuits requiring "significant rebuilds".

Icy conditions are forecast to continue over the next 24 hours, with frequent rain, sleet, hail and snow showers.

The Met Office has extended a yellow warning for snow and ice covering northern Scotland and north-east England until 11.59pm on Thursday.

The rest of the UK will remain cold but see some sunshine in parts, as well as some isolated freezing fog patches.

SSEN said it was working closely with various community support groups to ensure supplies were delivered where needed most in Shetland, and to set up mobile generators in communal areas such as public halls.

Shetland Island Council has urged anyone needing support to get in touch.

Council leader Emma Macdonald said: "This is a tremendously difficult time for many people whose homes will be cold and food and other supplies may be running low.

"I'd urge anyone with urgent health or care needs to get in touch, and our staff will respond to any request for help as best we can.

Schools across the area will remain closed due to the freezing temperatures, limited road access and power issues. The only school that will remain open is Fair Isle Primary School.

Scotland's Justice Secretary Keith Brown is expected to visit Shetland on Thursday to meet those leading the efforts to respond to the extreme weather and restore power supplies.