Can we believe a word that Gordon Brown says?

From Wednesday's PMQs per Hansard:

"Mr. Evennett: ... All our constituents are rightly concerned about transparency, expenses and cleaning up politics. With that in mind, now that it is clear that there was a £50,000 fund solely for the Prime Minister's use at his headquarters, will he explain why he did not declare this in the Register of Members' Financial Interests?

The Prime Minister: I know nothing about what the hon. Gentleman is talking about."

Is Gordon Brown saying he knows nothing of the allegations made by Peter Watt that there was a secret fund, worth a reported £50,000, which was held by the Labour Party for Gordon Brown's benefit? Or is he saying that there was no such secret fund? Is either explanation plausible?

"Mr. Cameron: What the Prime Minister has just said is completely at odds with what witness after witness has said to the Chilcot inquiry. Let us listen to what they have said. The former Defence Secretary said that we now have fewer helicopters because of the decisions that the Prime Minister took as Chancellor. The former Chief of the Defence Staff, General Walker, said that

"money ...was taken out of the helicopter budget".

Soldier after soldier has complained about the lack of body armour, vehicles and equipment, and we now know that the service chiefs threatened to resign en masse. Is it not time that the Prime Minister admitted to the mistakes that he made when he was Chancellor?

The Prime Minister: First, the Conservatives do not even know what their policy is for 2010 on spending on anything. Secondly, I have always taken seriously the need properly to fund our defence forces. In the 2002 spending review, which is the subject of discussion here, the defence estimate was the best for 20 years. The Defence Secretary at the time said it was an excellent settlement that allowed us to modernise the forces. In 2004, the defence management board made its own decisions. Let me remind the right hon. Gentleman that he stood on a platform at the last election to cut defence spending by £1.5 billion."

Really did the Conservatives propose £1.5 billion of defence cuts in their 2005 election campaign. Oddly The BBC reported in October 2004 that

"Frontline defence spending would increase by £2.7bn over three years under the Tories, they say. "

Eric Pickles has written to Gordon Brown urging him

"to admit to this fund’s existence, apologise for misleading the House and co-operate with any inquiries that John Lyon may wish to make."

I wonder if the Conservatives will query Gordon Brown's claims about their 2005 manifesto.