Veteran political correspondents like me recall Michael Morris, Deputy Speaker of the Commons from 1992-97, with a great deal of affection.

He carried off the role with plenty of brio and style. Michael Morris has since been deservedly elevated to the House of Lords, where he has taken the name of Lord Naseby.

As sometimes happens, he has gone sharply downhill since entering the upper house. Most troublingly he has become an apologist for the Sri Lankan government.

There is nothing wrong with standing up for unpopular or controversial causes: indeed it is admirable.

However, it is essential to adhere scrupulously to the facts when it comes to an event as grave and sensitive as the massacre of the Tamils in the final stages of the Sri Lankan civil war.

Unfortunately Lord Naseby has failed to be accurate in his recent attack on Channel 4’s harrowing documentaries: Sri Lanka’s Killing Fields, War Crimes Unpunished, and No Fire Zone.

In a parliamentary question on February 26th, Lord Naseby told peers that there is now “conclusive evidence that that film from Channel 4 features two key independent witnesses, so alleged, who were in fact fully paid-up members of the Tamil Tigers”. This statement is misleading.

One of the witnesses he refers to is a woman called Isaipriya. She was definitely a "fully paid-up" Tiger; she was in fact one of their TV personalities. Channel 4 never denied this in their documentaries: in War Crimes Unpunished, for instance, they refer to her as “the LTTE TV presenter Isaipriya.”

Lord Naseby’s suggestion that Isaipriya’s political affiliations are of any importance at all is troubling. Channel 4’s footage shows her dead, naked, with a single head wound and her hands tied behind her back – a clear victim of sexual abuse and summary execution. To treat a captive in such a way is a hideous breach of the Geneva Convention and her human rights; her political status is completely irrelevant.

The second witness Lord Naseby refers to is a British-Tamil health worker who gave terrible evidence of human rights abuses committed by government forces. She is still alive and I am not going to name her because I do not want to jeopardise her safety more than Lord Naseby has done already.

In her case there is absolutely no credible evidence of any kind that she is or ever has been a Tamil Tiger. Naseby’s statement relies on arguments from a propaganda book, Corrupted Journalism, published by a mysterious group called "Engage Sri Lanka".

Corrupted Journalism scarcely deals with her evidence, but attempts to discredit it by smearing her with unsubstantiated claims. For instance, it accuses her of operating under “at least four other names”, but three are just different spelling variations of the same name and the fourth from a random YouTube video; it accuses her of calling her "cousin" her "brother", despite the fact that this is conventional in Tamil culture.

Most strikingly, Corrupted Journalism brands her a “blatant apologist for terror and murder” and yet, in her only interview from the war zone with a foreign paper, she called for both sides to “stop fighting and start thinking about the civilians living here.” The position of Corrupted Journalism (and Lord Naseby) is absurd.

Lord Naseby can be commended for honestly declaring his interests as chairman of the All-Party British-Sri Lanka Group and a receiver of Sri Lankan government hospitality. I too should declare an interest, having in the past presented a number of documentaries for Channel 4. I have always been impressed by the professionalism and integrity of the people I have worked with.

Lord Naseby has given misleading testimony to the House of Lords, and his remarks have been picked up in Sri Lanka and are being used in defence of the regime.

The rules are clear. Those who make misleading statements to Parliament must correct the record at the first opportunity. Lord Naseby has misled parliament, and thus given comfort to perpetrators of state-sponsored terror. He must return to Parliament and withdraw his allegations.

( Peter Oborne is the Daily Telegraph's chief political commentator )