After years of talks, cigarettes are today being sold in plain packaging with graphic health warnings for the first time.
Here's what we know about the most radical overhaul of UK tobacco laws in a generation.
What will the new packs look like?
As seen in the picture above, all packs will be a dull green colour and will not feature any company logos.
Graphic health warnings must also cover 65% of the front and back.
Packaging of hand-rolled tobacco must also be in the same drab green colour.
What are the other changes?
Packs of 10 will no longer be available.
The smallest size smokers will be able to purchase will contain 20 cigarettes, or 30g of rolling tobacco, so there is enough room for the warnings.
Promotional statements such as "this product is free of additives" or "is less harmful than other brands" will also be barred.
Menthol cigarettes and "lipstick-style" packs aimed at women will be banned by 2020.
Why is it being introduced in the UK?
Smoking is the number one cause of preventable early death.
An estimated 100,000 people in the UK die every year from smoking-related diseases such as lung cancer or chronic obstructive pulmonary disease (COPD).
The government hopes the move will stop a new generation taking up the habit.
"If just a fraction of the 200,000 children in the UK who start smoking a year are discouraged, thousands of lives will be saved," Dr Penny Woods, the chief executive of the British Lung Foundation, said.
Has it been successful elsewhere?
Standardised packaging was introduced in Australia in December 2012 and figures suggest that the prevalence of smoking has dropped.
But I can still see the old packs still on sale?
That's because tobacco companies and shops still have a year to sell old stock and fully implement the changes.
After that, they will face severe penalties for flouting the rules.
How have tobacco companies reacted?
Unsurprisingly they were not happy and put up a fight.
Four of the world's biggest tobacco firms made a last-ditch legal challenge against the move but failed.
They argue that there is a lack of evidence plain packaging will put smokers off.
Simon Clark, director of the smokers' group Forest, said the new packaging rules "treat adults like children and teenagers like idiots".