The prime minister is expected to place his government’s counter-extremism policy at the heart of his speech to Conservative Party conference on Wednesday.

There’s little question that David Cameron’s tough rhetoric will go down well among activists, and it is likely to be well received in the press.

Yet, as Mr Cameron is surely aware, there are grave concerns that government policy invidiously targets Muslims.

There have been criticisms that the so-called Prevent strategy does not merely address violent extremism.

It has created a new category of thought crime, compromises free speech, and many people believe that it has turned British Muslims into a “suspect community”.

I believe that some of the criticisms are at least partly legitimate - and at Tory conference this week I gained a very troubling insight into how this type of McCarthyism works.

Several months ago I accepted an invitation from the Association of Chief Executives of Voluntary Organisations (ACEVO) to speak at an event in the conference centre this evening.

The subject under discussion was to be: “Faith and British Values: the Muslim Charities Question.”

I had already prepared my brief contribution when, late on Sunday afternoon, ACEVO informed that the event had been cancelled by the Conservative Party.

The cancellation followed an article on the Sunday Telegraph website by the well-known journalist Andrew Gilligan. The article made a number of profoundly damaging claims about Othman Moqbel, the main speaker at the event.

Mr Moqbel is chief executive of Human Appeal, a prominent charity part funded by the World Food Programme. It provides aid and relief to more than 20 countries around the world.

Mr Gilligan suggested that Human Appeal has close links with the Palestinian movement Hamas.

He also asserted that the Muslim Charities Forum (MCF), which represents a group of Muslim charities and which helped to organise the meeting, was closely associated with the Union of Good (a US-designated terrorist organisation).

The Conservative Party has refused to comment on the reasons for the cancellation. However, if the Sunday Telegraph claims that MCF and Human Appeal are linked to terrorism are true, there would be no reason at all to criticise the Conservative Party for its hasty decision.

But are the claims true?

Yesterday I examined Mr Gilligan’s article in detail. It contains a number of unsubstantiated claims, all of which Human Appeal denies.

There are also a number of obvious errors, which could have been rectified had Mr Gilligan chosen to speak to Human Appeal.

Given the gravity of the claims that he has made against the charity – that it is linked to terrorism – this failure to connect directly to the charity is nothing less than extraordinary. (In his defence Mr Gilligan told me that he dealt with Human Appeal indirectly, via ACEVO)

I will now examine Mr Gilligan’s claims about Human Appeal in the order in which they appeared in his article. Mr Gilligan states that “pictures from a Hamas event show the charity’s logo on the platform”.

I have tracked down what I think is the picture in question. The banner identifies the occasion as an “Event sponsored by the Prime Minister for Orphans of Palestine.”

Human Appeal say the event was nothing to do with them, and that the logo which appears in the picture is for Human Appeal UAE. They say that Human Appeal UAE “is a separate organisation with separate staff and trustees (although we do have one founding trustee in common) and it was definitely them that were involved in that event and not us”.

Andrew Gilligan did not draw his readers’ attention to the claim by Human Appeal UK that it is a separate organisation to Human Appeal UAE.

He ought to have done so, even if he did not believe it to be especially relevant.

Mr Gilligan’s next claimed that Human Appeal was named by the FBI in 2003 as having a “close relationship” with Hamas.

This is a bold and confident assertion, which after some searching I traced back to a late night Australian TV programme called Lateline, screened on 22 September 2003.

In it a reporter called Jonathan Harley asserts that he has seen such an FBI report. He does not however produce it, and I have not yet been able to get hold of Mr Harley to ask more about these claims.

A representative from Human Appeal appeared on the programme, and denied all links with Hamas. When I spoke to Human Appeal yesterday they told me this: “Human Appeal does not have and has never had links and/or a close relationship with Hamas and knows of no such allegation having been made by the FBI. We have employed a legal consultant to investigate this accusation previously and no such FBI document could be found.”

Mr Gilligan’s next claim concerned an assertion in a diplomatic cable published by Wikileaks that the US State Department accused Human Appeal of providing “financial support to organisations associated with Hamas”.

When I searched for this State Department claim I could not immediately find it (that certainly does not mean it does not exist!).

I put the claim to Human Appeal. This is what they said: “Presuming this means the likes of Union of Good. We are not part of this organisation and never agreed to join this organisation. We do not provide financial support to organisations associated with Hamas.”

According to Andrew Gilligan, the State Department claimed that “members of its [Human Appeal’s] field offices in Bosnia, Kosovo and Chechnya had connection to Al-Qaeda associates”.

This is clearly a very serious and damaging claim. When I put it to Human Appeal this is what they said: “We do not even work in two of these countries and we do not have a field office in Bosnia. However, Human Appeal UAE does have field offices in Bosnia and Kosovo.”

Mr Gilligan’s next assertion concerned the US Internal Revenue Service. He said that it had described Human Appeal as one of a number of charities which “finance terrorism and perpetrate violence”.

Human Appeal told me: “We are not aware of this description by the US Internal Revenue Service.

“It seems unlikely because we receive money transfers from the US all the time – as we receive funding from the UN’s Office for the Coordination of Humanitarian Affairs and the World Food Programme. Also, our lawyers have looked into this and there is no evidence of it.”

Mr Gilligan reported that Human Appeal hosted an event in July 2011 at Brent Town Hall with Hamas supporters.

Human Appeal told me that “this event did not take place”.

Some of Mr Gilligan's claims contained an important element of truth. For example the Sunday Telegraph journalist wrote that Human Appeal "hosted an event at the East London Mosque with one of Britain's most notorious hate preachers, Haytham al-Haddad".

Haddad has been attributed with having praised Osama bin Laden after his death in 2011. He has also described homosexuality as a "criminal act" and said female genital mutilation has a "proper" way of being carried out.

I tracked down the poster for this event, and Human Appeal's name does appear on it, though not as the host, which appears to have been a student group.

Human Appeal, judging from the poster, does seem to have been a significant financial beneficiary. When I put this to the charity, they said: "we would not have held an event where al-Haidad was invited".

They also seemed to accept they were wrong to have got involved, even as a third party beneficiary, saying that procedures have since been tightened up.

I don’t want to take sides between Mr Gilligan and Human Appeal. Indeed I have never had any dealings of any kind with the charity and had never heard of them until Sunday afternoon.

However Mr Gilligan’s allegations are very serious indeed. His article is certain to compromise Human Appeal’s efforts to attract donors. It is likely to appear on databases used by banks to check the credential of clients when providing banking facilities. I am not exaggerating when I say that Mr Gilligan’s article has the potential to put Human Appeal out of business completely.

This being the case, his claims should surely have been put very carefully in advance to Human Appeal, so that the charity could respond fully.

I now turn to a separate set of allegations in Mr Gilligan’s article. These concern the Muslim Charities Forum (MCF), which is an umbrella organisation for ten Muslim NGOs, which includes well-known names such as Islamic Relief and Muslim Aid.

In his Sunday Telegraph article Mr Gilligan said that “at least six of the ten charities in the MCF are or were members of the Union of Good”.

Islamic Relief, Muslim Hands, Muslim Aid, Human Relief Foundation and Human Appeal all strongly deny they have links to the Union of Good and say they were wrongly listed by the organisation as participants or members.

Some charities’ logos were reproduced without consent on the Union of Good website. Even though their names were removed when the error was flagged up, the Israelis appeared to have seized on this, publishing a list in 2008 of 36 banned Hamas-linked organisations that included some of the charities.

Furthermore the Charity Commission spoke six years ago to all the charities concerned, except Islamic Relief, about their alleged involvement with the Union of Good. All charities confirmed they weren’t members and the matter was closed.

There was no mention of this essential background in Mr Gilligan’s article.

It is also relevant to bear in mind that Human Appeal is registered with the Charity Commission. It would surely not enjoy this status if it were suspected by the British authorities of involvement in terrorism.

Under British counter-terrorism laws it would be banned in the UK if it had the links to Hamas which Mr Gilligan states.

Far from being banned Human Appeal told me last night that it “has been invited on numerous occasions by the United States Embassy in London to partake in discussions on aid work and counter terrorism.

“Furthermore, the charity’s employees were permitted to travel openly and freely through the United States in order to provide aid work during the humanitarian crisis in Haiti. If indeed Human Appeal was a ‘terror charity’, the US authorities clearly would not have treated the organisation and its employees in this manner.”

This is unanswerable. It is conceivable that Andrew Gilligan is right, and the US authorities are wrong. However Mr Gilligan has so far failed to substantiate his very serious claims.

Andrew Gilligan is a friend of mine and former colleague. I rang him up last night to ask him about his story. I asked him first of all why he had not approached Human Appeal.

“I approached them through ACEVO,” he said.

To be fair to Mr Gilligan, ACEVO did issue a statement, quoted at the bottom of Mr Gilligan’s Sunday Telegraph story, saying that Human Appeal denied links to terrorism.

I then asked about his claim that six MCF charities “are or were members of the Union of Good”. Shouldn’t he have put these very serious allegation to the Muslims charities themselves? I told Mr Gilligan that they all denied his claim.

“They are lying,” he said.

I asked Mr Gilligan how he knew that the FBI had accused Human Appeal of supporting Hamas. He referred to the Lateline report on Australian TV. But had he seen the FBI report referred to by Jonathan Harley?

Mr Gilligan told me he had.

Mr Gilligan then asked me: “Is this an inquisition?”

I replied that I was just asking him questions in the way that a reporter does. Mr Gilligan said that he wasn’t going to tolerate this any longer and put down the phone. Before doing so he said: “Their denials are not supported by evidence. What I wrote is supported by the facts.”

This may be so - but Mr Gilligan has yet to establish these facts.

The case of today’s cancelled conference about Muslim charities raises very serious questions that stretch far beyond journalism.

Why was Conservative Party chairman Lord Feldman so ready to cancel a conference event on the basis of one newspaper article making unproven allegations against respectable charities?

Would he have acted so hastily if they had not been Muslim charities?

Why didn’t he contact ACEVO, the MCF or Human Appeal and ask questions before cancelling the event?

And what about free speech?

Most worrying of all, Lord Feldman’s panicky response to a single newspaper article confirms the dark fears felt by many that the prime minister’s counter-terrorism strategy is about alienating and not engaging with British Muslims.

- Peter Oborne was British Press Awards Columnist of the Year 2013. He recently resigned as Chief Political Columnist of the Daily Telegraph. His books include The Triumph of the Political Class; The Rise of Political Lying;and Why the West is Wrong about Nuclear Iran.

Alex Delmar-Morgan contributed to this report.

The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Middle East Eye.

Photo: British Conservative Party Chairman Lord Andrew Feldman arrives for a weekly cabinet meeting in Downing Street, central London, on May 12, 2015 (AFP)