Mandelson forgets manifesto details?

Peter Mandelson has just told Gary Gibbon that there has never been a promise for electoral reform through a referendum before. Has he forgotten the 1997 Labour Manifesto he helped write?

We are committed to a referendum on the voting system for the House of Commons. An independent commission on voting systems will be appointed early to recommend a proportional alternative to the first-past-the-post system.

Fib or memory loss?