Fake alcohol containing potentially-lethal chemicals capable of turning drinkers blind is being found in Norwich shops.

Trading Standards has seized around 100 bottles of illegal alcohol including wine, vodka and champagne from Norfolk stores since 2010.

The counterfeit drinks are riddled with dangerous chemicals such as isopropyl, used in industrial cleaning products, methanol, found in anti-freeze and capable of causing blindness, and chloroform, used to produce dyes and pesticides.

Bottles of the counterfeit alcohol were found hidden in the ceiling of one Norwich shop, while before Christmas a student in the city fell ill after drinking an illicit vodka called Drop.

Assistant director for public protection at Norfolk County Council, David Collinson, said: 'They use impure alcohol which is particularly dangerous.

'There is no traceability for them and therefore no reputation for any manufacturer to lose. They don't care how the alcohol is made or how safe it is.'

Mr Collinson said the counterfeit drinks were being imported from abroad making it hard to trace the source, although some factories have been found in the UK.

Five men died and one was seriously injured after an explosion at an illegal vodka distillery in Boston, Lincolnshire last July.

Produced by criminal gangs, the fake alcohol is often sold to small stores and off-licences by suppliers who target a clutch of shops and leave quickly to avoid detection.

The suppliers tend to deliver the damaging drink to shops on main roads, so they can get out of the area fast.

But unlike with other counterfeit products seized by Trading Standards such as DVDs or clothes, where buyers may purchase the goods knowing they are fake because they are cheaper, people buying counterfeit alcohol are often being tricked into thinking it is the real product.

As well as creating their own illicit drink brands such as Passion, Admiral and Drop Vodka, the counterfeiters are also mimicking well-known brands such as Jacob's Creek wine, Smirnoff and Glens vodka and champagnes.

Bottles of fake Jacob's Creek seized in Norfolk had the wine's country of origin, Australia, spelt incorrectly, and spelling mistakes on labels, as well as glue marks, poor seals and no duty stamp are all warning signs for consumers to look out for.

Cheap prices are also a give-away with some of the vodka found on sale for as little as �6, yet duty on a 70cl bottle with 37.5pc alcohol is �6.70.

Norfolk Trading Standards has responded by visiting shops to warn them and carrying out inspections.

Alcohol fraud costs the UK about �1bn a year in lost revenue, including �300m from illegal spirit sales, according to government estimates.

With plans to introduce a minimum alcohol price the demand for black market spirits, both illegally imported and illicitly produced, could increase.

Mr Collinson said: 'Where there is a differential in price there is an incentive for people to carry out transactions in illegal goods, but the health advantage (of minimum pricing) outweighs that change.'

Warning signs of illicit alcohol include:

• Glue marks around labels or self-adhesive labels which have been stuck on by hand and are not straight.

• Loose bottle tops with inferior seals.

• Bottles of the same product filled to different levels.

• No manufacturer's name and address.

• No duty stamp.

• Spelling mistakes on labels or labels that lack quality in their colour or feel.

•To report counterfeit alcohol or to get advice call the Citizens Advice consumer helpline on 08454 04 05 06.