A Sky News investigation has discovered shops in London selling unlicensed or prescription-only skin-bleaching products.

In Peckham, southeast London, we purchased a tube of Fashion Fair Cream from two shops.

This product is unlicensed in the UK and contains the ingredient Clobetasol Propionate, a prescription-only steroid used to treat conditions such as eczema or psoriasis.

Due to the potential for harmful side-effects, its use should be controlled by a doctor, and it should not be sold over the counter to the general public. Also in Peckham we purchased Movate, a cream that has not been tested or licensed in the UK, and which also contains prescription-only ingredients. In Brixton, we found Dermovate on sale at a beauty shop.

Although licensed by the Medicines and Healthcare Regulatory Agency, it is illegal to sell in the UK without prescription.

After first telling our reporter they did not stock the item, the assistant found some behind the counter and sold it to us for £4.99.

Most skin-whitening creams are safe and legal to sell to the public. They are marketed to women from Afro-Caribbean and Asian backgrounds where there can be a perception that fairer skin is more attractive.

But there is an illegal market in products which contain stronger ingredients that can cause uneven colour loss, intense skin irritations, rashes or permanent bleaching.

Hansa Dabee, who is Asian, started using skin-bleaching products when she was fifteen, after experiencing what she describes as 'cultural pressure' to have fairer skin.

"I wanted to make my skin appear lighter because I wanted my complexion to be clearer and I thought it would make me more attractive.

"I used to watch Bollywood films and the actors appeared to be a lot lighter than your average Asian. They went on to endorse lightening creams in advertisements.

"At school the boys would drool over pictures of Bollywood actresses on their phones. They were fascinated with how fair and light they were.

"Every time I used it I thought, 'Wow, my skin looks so much clearer'. But I stopped using lightening cream about a year ago after considering the massive dangers it could have."

Singer Beyonce recently attracted controversy when she appeared in photographs that looked as though they had been digitally enhanced to lighten her skin. Local authorities have taken action to clamp down on shops illegally retailing un-licensed bleaching creams.

Southwark Council in South London have successfully prosecuted 15 shops in the last seven years.

When confronted, the shops we visited all denied selling the products.