Tough restrictions imposed on Glasgow and neighbouring councils are due to end on December 11.

But public health chiefs are still worried about the level of infection spreading in communities.

First Minister Nicola Sturgeon said it is "likely" she will be able to make major changes at the next review.

That doesn't mean all 11 councils at level 4 will find themselves with significantly lighter rules.

And some councils are still facing tougher restrictions unless covid rates fall.

Here, we explain what happens next as Scotland tries to keep a lid on coronavirus before Christmas.

How does the system work?

Scotland's five-tier system started at the end of October in an attempt to push infection rates down in targeted areas.

Restrictions start at level 0, which is effectively "normal", and rise to level 4 with heavy restrictions on socialising, gyms, leisure and hospitality.

Glasgow streets are quiet as shops shut before Christmas.

Glasgow and 10 neighbouring councils were forced into the highest category within weeks of the system being set up.

The rules were imposed in west central Scotland for three weeks, leading to speculation about what might happen at the next review.

So what happens next?

Nicola Sturgeon will update the Scottish Parliament on Tuesday December 8 with the next phase of the tier system.

The decisions announced then will apply from December 11, the date previously set as the end of the intended level 4 crackdown.

The review will look at all of Scotland's 32 councils.

Some regions, especially those in the rural south, are hoping to move to level 1. There could be good news in the Highlands for people wanting to mix indoors.

What do public health chiefs say?

Chief medical officer for Scotland, Dr Gregor Smith, said officials have been looking at level 4 regions closely and had another meeting on Thursday December 3.

No decisions have been taken yet, but he said: "We are very encouraged by the trajectory in a lot of these areas. In truth, after these restrictions were applied it's only really this week we've seen the impact fully coming through."

At the last review, Sturgeon said: "As we go deeper into the winter period, there are a number of factors that may well push transmission up again. So we could see cases and resulting illness and death start to rise again.

"That means we have an interest in driving cases as low as we can now. That necessitates continued caution."

How long will the tiers system be in place?

Reviews are held every week based on public health data.

There is no end point for the five-tier system yet.

The light-touch five-day break over Christmas in the UK raises fears about the need to impose strict rules again if infections - as expected - rise in the new year.

The decision to permit family gatherings over Christmas was agreed across the UK.

What are the main differences between levels?

Almost everyone has to live with the same restrictions on mixing in each other’s houses whatever level has been imposed.

The key differences are on access to retail and hospitality at the higher end of the scale.

People in level 4 areas can't go to pubs or restaurants, while in level 2 areas, alcohol can be purchased inside a pub during the day.

Travel restrictions were imposed last month and had already led to 33 penalties from police by the end of November. People are not supposed to travel into of from level 3 and 4 zones. No one is supposed to travel over the border to England unless for essential reasons.

What will happen at Christmas?

A UK-wide agreement means travel restrictions are being lifted regardless of levels all over Britain.

Three households can form groups known as "bubbles", despite strong warnings to avoid unnecessary risks.

The dates from December 23 to 27.

Scotland's lockdown levels by council area

Level 3

  • Orkney
  • Shetland
  • Argyll and Bute - only covers islands of Coll, Colonsay, Erraid, Gometra, Iona, Islay, Jura, Mull, Oronsay, Tiree, Ulva.
  • Highland islands, except Skye.

Level 4

  • Highland (Mainland and Skye)
  • Argyll and Bute (Mainland)
  • Western Isles
  • Moray
  • Dumfries and Galloway
  • Scottish Borders
  • Inverclyde
  • Falkirk
  • Angus
  • Edinburgh
  • East Lothian
  • Clackmannanshire
  • Dundee City
  • Aberdeen City
  • Aberdeenshire
  • Fife
  • North Ayrshire
  • Midlothian
  • Perth and Kinross
  • East Ayrshire
  • East Dunbartonshire
  • East Renfrewshire
  • Glasgow
  • North Lanarkshire
  • Renfrewshire
  • South Ayrshire
  • South Lanarkshire
  • Stirling
  • West Dunbartonshire
  • West Lothian