One is that it's in the Daily Telegraph, which is not just a C/conservative newspaper, but has consistently shown itself to be a campaigning Eurosceptic newspaper.

In itself this is not enough, of course. But a comparison of Waterfield's article with the Irish Times one he quotes from reveals cherry-picking and tendentious interpretation. An example of cherry-picking: "Ireland is 1 per cent of the EU" is quoted as if it is part of Giscard's reasoning about referendums, but in fact he said it in the context of whether Ireland should have its own permanent commissioner:

ireland.com - The Irish Times - Thu, Jun 26, 2008 - Giscard rules out keeping of Irish commissioner

"Ireland is 1 per cent of the EU. You're not going to have your own commissioner. It isn't reasonable

Waterfield also ignores (as Migeru points out) Giscard's denunciation of the unfair use of what he has said about the unreadable nature of the Lisbon Treaty, which Giscard in fact criticised as "unworthy" and likely to encourage people in the idea they were being led by the nose.

And the byline claiming Giscard said future referendums would be ignored is tendentious. Giscard says

"there is no alternative" to a second Irish vote

which is not the same as saying referendums will be ignored. His words quoted by Waterfield in support of that idea

"We are evolving towards majority voting because if we stay with unanimity, we will do nothing," he said.

are about majority/unanimity principles in general, in response to a question asking whether the EU was not founded on the unanimity principle.

So it's a cut-and-paste job by Waterfield.

The final point is that Giscard is not as important as he's made out to be.

Waterfield:

The former President of France drafted the old Constitution

He did not. He chaired the drafting committee, and no doubt had considerable influence, but he wasn't alone in charge. And he has lost, rather than gained, influence as a result of the "Constitution" (he has been criticised for wanting to give it that grand title) being rejected - in his own country. So he's an elder statesman, unfortunately a narcissistic one who likes the sound of his own voice, but with no really considerable power.

But a vain and talkative former French president is quite a gift to the Eurosceptics. The sub-text in the Telegraph article, imo, is "here are the French dictating to everyone again". Par for the course from the UK press.