It will come as little, if any comfort, in the days and months to come, that targeted attacks on groups of children at play are mercifully rare in the UK.

The worst in British history was the Dunblane massacre in March 1996 when a gunman walked into a school and killed 16 children and a teacher, before taking his own life. Thomas Hamilton, armed with guns, carried out his attack in the picturesque Scottish village, opening fire on a class of five- and six-year-olds.

Hamilton, 43, described as a loner, had previously been removed from the Scouts after concerns were raised about him, fuelling a sense of grievance. The Dunblane massacre led to a toughening of firearms law, making them much harder to obtain.

Later, Hamilton was cited by Horrett Campbell, who was convicted of an attack on an infants school in Wolverhampton, armed with a machete and homemade flame thrower in July 1996. Campbell was convicted of wounding seven people and adults. In police interviews, he outlined the sense of perceived grievance that drove his attack.

The jury at Stafford crown court heard Campbell, who suffered from paranoid schizophrenia, told police: “They hadn’t done anything personally but they had contributed to the pressures I’ve had by jeering at me if I walked past.

They tease me, the kids at school. They just say things like I’m a loser and a failure and that. They picked on me calling me names. They called me ‘celibacy’ and words like ‘tramp’.”

Campbell, then 33, said he felt in a similar position to Hamilton: “I see myself having difficulties and being sort of victimised and pressurised unnecessarily. So I think I should share that pressure with other people and attacked some people like I did.”

Campbell was ordered to be detained indefinitely.

In 1994, Garnet Bell, 47, was jailed for three life terms for attempted murder and three for grievous bodily harm for a flame thrower attack at Sullivan upper school in Holywood, County Down. He suffered from an untreated personality disorder and was a former pupil at the school.

For Merseyside police their investigation into the attack on the children’s dance class in Southport is just beginning.

Detectives will be rushing to identify any addresses their suspect has links to and searching them. They will also be trying to identify any electronics, such as phones or computers, gain entry into the devices and scour their contents for any clues.

The urgent need is to satisfy themselves that the suspect acted alone in the planning of the attack. Other considerations will be seeking clues as to motive for the selection of the dance class and why it was visited with such violence.

The suspect’s mental health will be examined as will whether the suspect had any contact with the statutory agencies – police, courts, health services and social services – before the attacks and whether there was any hint of what was to come.

As people in Southport try to deal with the horror, there are likely to be three formal processes after the attack.

A criminal trial of the suspect, inquests into the deaths and a specific one into the circumstances surrounding the death of a child.

Each local authority area has a child death overview panel that carries out an inquiry when a child is killed.

For emergency services workers who were first on the scene, their bosses will try to alleviate any trauma. The Merseyside chief constable, Serena Kennedy, said her officers were “shocked” by what they found. For police, the Merseyside force offers a programme called TRIM (trauma risk management). After a debrief, officers will be encouraged to take up one-to-one counselling.

Security at the dance class in Southport would have been light to nonexistent. Such classes run on a financial shoestring.

One senior police officer, asked about any question of tightening security at clubs for children, said it was highly unlikely: “You can’t have children’s classes operating like a prison.”

• Merseyside
• analysis