Why telling porkies is not advisable

The Guardian reports:

"The home secretary today defended the government's decision not to hold a full public inquiry into the July 7 bombings.
Charles Clarke spoke as some of the victims of the bombings, Muslim leaders and Conservatives criticised the decision, which was confirmed by the Home Office last night.
Instead of an independent judicial inquiry, a senior civil servant will compile a "narrative" on the attacks in London using evidence compiled by the police and two House of Commons select committees.
The narrative may also, in an unprecedented move, make public some of the secret intelligence about the four bombers, who killed themselves and 52 people."

So there will be a narrative. But, after the dodgy dossiers on Iraq, who will believe it? The Government's credibility is shot. Even if they want to tell the truth (which is a big assumption), no-one will trust a word.