High on the idea that the "domains" of museums, libraries and archives are natural bedfellows brought together by knowledge, IT, schools, lifelong learning and "cross-platform" delivery we were all encouraged to act and think as one sector.
But are we natural bedfellows? Does brigading museums, libraries and archives together make sense and what has been achieved since 1999?
There is some rationale behind the MLA's mantra. The cross-sectoral dream is fulfilled within some sections of English local government and this has recently been boosted by the Passion for Excellence report encouraging authorities to bring services together and work in partnership.
Museums, libraries and archives share many similar characteristics; their services can be delivered jointly and the digital revolution offers exciting possibilities.
But is it true that museums, libraries and archives are simply different branches of the same sector, indistinguishable to the user? No. The purpose and role of, for instance, museums and libraries is fundamentally different as is the experience of engaging with them. Museums and archives are about collections, libraries are not.
The fit between museums, libraries and archives is really not that tight. Sixty-nine per cent of museums in England lie outside local government.
Museums have no real equivalent of company, legal and medical libraries; museums make substantial use of volunteers, libraries don't; independent charitable trusts make up half of the museum sector yet there is no real equivalent in libraries and archives; the national museums often have their own libraries and archives.
Many marketing concerns of museums have little or no resonance in libraries and archives - visitor income, tourists, shops and cafes.
Many local authorities do run museums, libraries and archives, but few are housed in the same building and by no means all are run by the same department.
Eight years on, what sort of progress has been made to support the idea that we are one sector? At a strategic level there has been some joint work and there is a greater willingness to understand each other. But have we seen a real change in structures and the service offered to the public? Barely.
Museums, libraries and archives working together is a worthy idea, but it is just one of many partnership possibilities. Museums' natural partners might be the arts, heritage, sport or, increasingly, children's services.
But the case for museums, libraries and archives being a coherent sector was never articulated and nothing has changed. The insistence of the MLA on promoting this holy trinity above all else looks, at best, irrelevant to most museums and, at worst, counterproductive.
Mark Taylor is the director of the Museums Association
Museums Journal, October 2008, Comment p17