A mum whose daughter died after taking a legal high believes not enough is being done to outlaw them.

Margaret Moyle spoke of her frustration as figures from an independent thinktank showed the number of police incidents involving the substances in Essex rose 11-fold from 11 cases in 2010 to 125 last year.

The Centre for Social Justice (CSJ), which published the figures last week, has called for a "robust response" from the Government, including new police powers to close shops that persist in selling legal highs.

Mrs Moyle's daughter Sarah Forsyth took Ivory Wave bath salts on and off for nearly a year to try and lose weight.

She died in August 2010 after slipping into a coma 12 days.

Mrs Moyle, of Cant Way, Braintree, said: "I wish these things weren't being sold but I just wonder what could be done to stop it?

"I don't know what the police can do because a lot of the time people say if you stop it openly, then it goes underground, which makes it worse."