Tasers are electroshock weapons that have a peak voltage of 50,000 volts. According to the Association of Chief Police Officers this "drops to 1,200 volts" when the charge travels "across the human body", with a current of 0.0021 amps. In the UK, seven people have died following their use in the last ten years.

Campbell's statements were made in response to a report by the Independent Police Complaints Commission (IPCC), which described the use of Tasers in "drive stun" mode as "purely a means of pain compliance".

The IPCC's review of Taser complaints and incidents from 2004 to 2013 found that: "in several of the cases we reviewed, where was used for the purpose of gaining compliance, it in fact had the opposite effect, stimulating further resistance."

Tasers are still being used in drive stun mode despite the fact that officers are no longer trained in the method. Campbell said that "officers were still being given demonstrations" on how to use the weapons in this way.

Use of Tasers more than doubled overall between 2009 and 2013. Some forces have seen steeper increases - for example, Devon and Cornwall police's use of Tasers increased "from 3,128 in 2009 up to 10,380 in 2013."

Home Office figures published earlier this year show that in 2013 alone, use increased by 27% on 2012.

As well as concerns about the use of Tasers in "drive stun" mode, the IPCC report also highlighted concerns over:

• Taser use on people with mental health difficulties, the young and other vulnerable people; and
• Taser use in confined spaces - for example, a custody cell.

Recently a senior special constable (volunteer police officer) called for a further expansion in Taser use, saying that police volunteers should be able to use the weapons "to allow them to control violent offenders".