A senior Ukip figure has been branded "shameful" after claiming a "holocaust of our children" was being orchestrated by Muslim sex gangs in English towns and cities.

Alan Craig, the party's children and families spokesman, said the practice of preying on mainly "white English girls" could be traced right back "to Mohammed himself", in a speech at the party's annual conference in Birmingham.

He described the issue as "the biggest social crime and scandal in our country for 200 years", accusing authorities of turning a blind eye to what became high-profile cases in Rotherham, Telford and Oxford.

However the anti-extremism think tank Quilliam, which produced a report quoted by Mr Craig, criticised his speech for misquoting it and using "alarmist and unnecessary language".

Director of policy David Toube said: "Alan Craig's misuse of Holocaust imagery to describe the grooming gangs case is shameful.

"The Holocaust constituted the industrialised murder, by the Nazi state, of over a million Jewish children. The grooming gangs cases involved a failure to prevent and, initially, to prosecute criminals who raped scores of vulnerable girls.

"Quilliam has spoken out loudly against the scandalous failure to address these crimes. But to compare these evil acts to the Holocaust is disgraceful."

Mr Craig is a Christian campaigner and former leader of the Christian Peoples Alliance. His selection as a Ukip candidate at the 2015 general election caused controversy over alleged homophobia following his comments about "gay rights stormtroopers".

Speaking in Birmingham on Friday, he added that the majority of - but not all - the victims of grooming gangs had been white girls.

In a speech greeted by a standing ovation from delegates, Mr Craig said the problem was "an issue literally made in hell".

He initially said he would not talk about the perpetrators, something that was greeted by a shout of "shame" from inside the hall.

He said: "I'm talking about the decades of abuse, grooming, assaulting, raping, drugging of underage girls up and down the country.

"I'm talking about something that has happened outside schools, outside children's homes, in shopping malls, quite openly in public up and down the country in towns and cities.

"What has happened over the last decade is nothing less - and I use this word advisedly - a holocaust.

"It has been a holocaust of our children, of our daughters."

He went on to accuse politicians of "refusing to name the issue" and hiding behind phrases for attackers like "men" and "Asian men, as if the Chinese and Japanese were involved in doing this sort of thing".

He went on to describe a Quilliam report, saying: "They said quite clearly that overwhelmingly the perpetrators are from Pakistani and Muslim backgrounds.

"And they traced a major part of the influence back to the Islamic faith and to Mohammed himself."

But the think tank said the report which he referred to said acceptance of child marriage among some Sunni Muslims "stems from the selective reading of hadith literature" which is disputed by other followers of the faith "as it is in conflict with several other historical accounts suggesting that this report is inaccurate".

A spokesman added: "While we discuss that the scale and severity of this crime is significant and needs to be dealt with swiftly, in the report, we caution against exaggerating the issue."

He pointed out that a child sexual exploitation study in 2011 had found that 0.01% of the UK's Asian population (and 0.03% of the UK's ethnically Pakistani population) were child sex offenders.

He added: "Thus, to say that the Asian population living in the UK has a CSE (child sexual exploitation) problem, or even that the British Pakistani community has a CSE problem is wholly inaccurate and a misrepresentation of the facts."