A ban on displaying tobacco in small shops comes into force today.

The display of tobacco products, which has been illegal for large stores and supermarkets since 2012, will now be prohibited in all premises.

The ban has been heralded as an important breakthrough by campaign group Action on Smoking and Health (Ash), which said it strongly supports this “important step forward”.

Hazel Cheeseman, director of policy at Ash, said: “Two-thirds of smokers start before the age of 18, so it is vital that everything is done to put tobacco out of sight to protect future generations.

“The display ban in small shops will work hand in hand with standardised packs, which will be introduced in May 2016, to further protect children from glitzy tobacco packaging.”

But retailers have branded the ban “unnecessary”, saying there is not enough proof that it will have a real effect on child smoking rates.

Suleman Khonat, s pokesman for the Tobacco Retailers’ Alliance, said: “The introduction of the display ban into larger shops hasn’t even been evaluated, so how do we know it will work in smaller shops? Of course retailers will need to comply with the law but this is a further unnecessary measure that will hit small businesses.

“There will be real difficulties around its application, including longer transaction times, and the costs of implementation such as the installation of new gantries. Coming on top of plain packaging, it is an unnecessary burden on shops already struggling with red tape.

“There are other more effective means of stopping children from taking up smoking.”

The Tobacco Retailers’ Alliance, which said tobacco represents about a third of the average newsagent’s turnover, suggested that, rather than banning the display of the products, the Government should crack down harder on the tobacco black market and increase resources to enforce the existing law on the prohibition of sales to under-18s.

But the Department of Health said ahead of the initial 2012 ban that evidence showed cigarette displays “encourage young people to start smoking”, while covering the displays would help them to “resist temptation” and “help support adults who are trying to quit”.

Alison Cox, Cancer Research UK’s director of cancer prevention, said the ban is a positive step towards reducing the number of young smokers.

 She said: “Smoking kills 100,000 people every year in the UK. It’s great that tobacco will no longer be in plain view of children and young people every time they go into a shop.”Research shows that children exposed to tobacco displays are more likely to start smoking and removing these eye-catching, colourful walls of cigarettes will protect them from tobacco marketing.”