The number of disability hate crimes reported to police has reached a record high, sparking concerns that the Coalition's "anti-scrounger" rhetoric is fuelling hostility to the most vulnerable members of society. A total of 1,942 disability hate crimes were recorded by police forces in England, Wales and Northern Ireland last year.

That figure, based on Freedom of Information answers supplied by 43 of 44 forces, represents a 14 per cent rise on 2010. Disability hate crime has doubled since the start of the financial crisis in 2008. Despite the rise, the number of people convicted for the crime actually fell last year. Only 523 people were found guilty of a disability hate crime in 2011, The Independent has discovered, down 5 per cent from 2010. It suggests that barely one in four reported crimes leads to a conviction – a ratio that got worse last year.

Charities expressed grave concern at the rise in reported incidents. Guy Parckar, head of policy and campaigns at Leonard Cheshire Disability, said: "The impact of hate crime simply cannot be overestimated, and these figures suggest that police authorities and local and central government must all look again at what they are doing to tackle disability hate crime."

While the Association of Chief Police Officers says the rise in cases can be explained in part by efforts to encourage more victims to come forward, many disability groups fear the figures reflect society's growing antipathy towards the disabled community.

"There are historical parallels," warns Katharine Quarmby, the author of Scapegoat: Why We Are Failing Disabled People, who has grown alarmed by the levels of "benefit scrounger" abuse aimed at disabled people. "If you have a group that is blamed for economic downturn, terrible things can happen to them."

Last year the Glasgow Media Trust found the public believed between 50 and 70 per cent of those on disability benefits were fraudulent. The actual number is likely to be between 1 and 2 per cent. The same report found that there has been a tripling in the use of words such as "scrounger", "cheat" and "skiver" in tabloid stories on disability in the past five years.

"Iain Duncan Smith [the Work and Pensions Secretary] is saying 'We're going to push through these benefit reforms' and hinting strongly that lots of people on disability benefits are scroungers," Quarmby says. "That kind of rhetoric leads to disability hate crime on the streets."

Disability charities receive a constant flow of reports about incidents that are never reported to police – from families who have been forced out of their homes by relentless targeting, to disabled teenagers who avoid groups of strangers for fear of what might be said to them.

Campaigners fear that disability hate crime prosecutions are being undermined because of a perception in the criminal justice system that evidence given by mentally disabled people is unreliable.

Jo Davies from Mencap said: "If someone with a learning disability is on a witness stand being pressed for certain details, they may end up being confused by the cross-examination. And then different elements of the case can fall apart."

Mencap calls for more support for disabled witnesses, such as better pre-trial preparation and more opportunities to give evidence via video link.

Case study: Since the attack I think to myself all the time, why me?

In March 2011, four people were sent to prison for a total of 27 years after attacking Louise Hewitt. It was one of the most brutal cases of disability hate crime ever to come to court. Here she tells her story.

When I was eight my mum gave me up to foster care. I had an assessment a few years later which said 'you have moderate learning difficulties'. That's the category they gave me.

After 10 years with my foster family, I went to a special boarding college then into supported housing. I eventually moved to Torquay, which is where the attack happened.

I visited a friend one day and there were these homeless people there, one of whom was called Karl. They told me they didn't have anywhere to live, so I let them stay in my house share for £50 a fortnight.

One afternoon we all had a drink at the house of a woman called Maryanne, who had been going out with Karl. He asked me if she was cheating on him. I said yes. I was telling the truth, but she denied it.

Both of them kept shouting at me 'you're lying, you're lying'. Everyone was egging on everyone else to throw in the first punch. Then Maryanne lunged at me, got her stiletto and hit me in the face. I tried to get away but they wouldn't let me. They kept punching and kicking me.

Then I was frog-marched to a house next door, where I was held hostage again. They locked the doors and shut all the curtains. Karl was standing near the door giving orders of what to do to me. I can still see myself sat in that room. I was beaten with saucepans and plates. They dumped a big plant pot over my head. They broke my nose. They cut me with a kitchen knife behind my ear and on my arm. One of them tried to strangle me.

When the case eventually came to court, I went along for the verdict. All I heard was each person's name and the years they got each, and I thought, 'Yes, I've won this one'.