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These are the pills in current circulation that you should not be taking

Some contain four times over the recommended dose of MDMA

With the news that two young people died at at festival in Portsmouth after taking unsafe drugs, fresh calls have been made for on site drug-testing at festivals which would allow users to test the purity of their drugs.

We spoke to The Loop, a company who attend festivals and test people's drugs. They've just been at Love Saves The Day in Bristol, and their sole purpose is to help those who may decide to take drugs at any point throughout the festival.

Close attention is paid to testing MDMA, which according to Dancesafe is "about as safe as skydiving". It became apparent that when most people buy MD, they're unlikely to know whether the product they are purchasing is pure.

The Loop warn drug-users that "drugs sold as MDMA, Molly or Ecstasy are often impure and 87 per cent of 'Molly' analysed by the DEA between 2009 and 2013 contained 0 per cent MDMA, and instead mostly contained bath salts".

At festivals, The Loop find much lower levels of mis-sold samples in the UK, and the presence of unexpectedly pure powders or strong crystals is by far the biggest risk they currently deal with. They test huge amounts of drugs which end up being flagged as dangerous. Here are the pills that are in current circulation which are found to be unsafe:

Pink heart pill, found in Bristol

These pills found in Bristol contained n-methylpentylone, which is often sold as MDMA because it looks very similar to the real thing. However, its side effects can be very severe, causing anxiety, panic attacks, and an inability to sleep for up to 48 hours.

'Punisher', found in Bristol

These pills which were also found in Bristol contain a dangerously high amount of MDMA by anyone's standards. The average dose for most people is 120 milligrams of MDMA per session, so anything close to 300 milligrams could bring very unpleasant side effects.

Silver bar pill, in circulation across the UK since 2015

These tablets are notoriously dangerous and people should be weary of them before taking them. The amount of MDMA they contain across batches is known to be inconsistent, and you could end up consuming up to four times the amount that is deemed to be 'safe'.

The Loop advise you to seek medical attention if you feel unwell at any point.