In 2004 Newcastle was the most expensive place in the UK to buy amphetamine at �15 a gram, now it is the cheapest at �2 a gram.

Local drugs workers say it has become a popular partner drug for heroin users.

The survey, across 15 towns and cities, was carried out among 40 frontline drug services in July by Druglink magazine and published by DrugScope.

'Thriving market'

The aim is to give a snapshot of current prices, helping police and drugs workers to respond quickly to emerging trends in their areas.

It also found that in Newcastle the price of cocaine has dropped by a third, and the city has some of the most expensive herbal cannabis, and some of the cheapest cannabis resin in the UK.

Harry Shapiro, editor of Druglink said: "In some parts of the UK the amphetamine market has all but disappeared, whereas in Newcastle it is thriving.

"The city also has vastly differing cannabis markets, with its herbal cannabis being amongst the most expensive in the UK, whilst its cannabis resin is amongst the cheapest."