Half of the children shot by police with stun guns, and a third of those restrained using spit hoods, in England are black or from other minority ethnic groups, according to figures obtained by children’s rights campaigners.

The data, compiled from freedom of information requests, showed that in the first nine months of last year police across England used electronic stun guns 839 times on people aged under 18, compared with 879 uses on children in the whole of 2017.

Researchers also found a sharp rise in the use of spit hoods against children, with 114 incidents in the first nine months of 2019, more than double the 47 uses in the whole of 2017.

The findings are published in a report on Tuesday by the Children’s Rights Alliance for England (CRAE), which pointed to an extreme disproportionality in the use of both weapons against children of colour, particularly in London.

Of the children who had stun guns used against them in England, 51% were from a minority background, rising to about 70% in London – where black children alone accounted for 54% of incidents. Across England, 34% of children bound with spit hoods were from ethnic minorities. In London this figure rose to 72%.

Stun-gun use includes any occasion in which the weapons are drawn or their laser sights are pointed, as well as incidents in which the device is fired or activated.

In December the Home Office published data on police use of force for the first time, which showed that nearly one in 10 incidents involved a child – including 519 incidents involving children under 11.

But the CRAE report argued that these figures are likely to downplay the true scale of the use of force against children. “During each of these incidents multiple tactics may have been used but they will only be recorded as one incident,” it said. “A key problem with these statistics is that they don’t disaggregate by age and ethnicity and it is likely that there is underreporting of figures.”

Researchers noted some improvements. The number of child arrests fell from 87,525 in 2016 to 79,012 in 2017 – an overall reduction of more than two-thirds in seven years. Fewer children were also entering the youth justice system, with 14,400 first-time entrants in 2017-18 compared with 16,500 the year before. In 2017-18 the number of children cautioned or sentenced was 26,700 – a 82% drop in a decade.

However, the report pointed to the use of children as spies – an issue taken up by CRAE’s parent organisation, Just For Kids Law – as particularly concerning.

Louise King, CRAE’s director, said: “It is alarming that there have been year-on-year rises in the use of Tasers and spit hoods against children, including children under 11 years old. Both of these devices can cause serious psychological suffering as well as physical harm and even fatalities. Children have also told us how frightening and traumatising the threat of their use can be.

“The use of Tasers and spit hoods against children should be prohibited. As an immediate first step, police regulations, training and guidance must be revised to ensure this equipment is only ever used as an absolute last resort when all other options have been exhausted.”