Is going to the Copenhagen Summit in December 2009 going to help to build a mass movement that takes non-violent direct action on climate change in the United Kingdom?
Leaving aside the tricky question of “is disrupting the negotiations a good idea”? (In order to achieve what?) there are other tricky questions that need to be asked:

What are the dangers of spending so much time and energy organising for a summit?

What would short-term success at the summit look like?

And what would it cost?

What projects won't go forward?

Or go forward with less vigour than they otherwise would have?

What happens if the most dedicated and high-profile activists are focussed on preparing for- and then heading off- to Copenhagen for two or three weeks?

Alternatives?
While the world's leaders talk (again) at Copenhagen about reducing greenhouse gas emissions, ordinary people could be non-violently DOING it- through individual and collective actions- in villages, towns and cities all over the world.

Every day while the negotiations happen, there could be a whole range of actions, from the very very non-arrestable through to the harder end of things. Different days could focus on different industries (aviation, power generation, oil industry, agriculture, transport, cement, forestry etc) and/or different countries could "adopt" different days, in a rolling programme of actions.

The 15 months from September 08 to December 09 could be spent on small-scale direct actions scattered across the countries of the UK, from open and fluffy through to closed actions, with a constant focus on "December 09 and beyond".

Resources could be made available on the web on paper and via social centres and friendship groups on how each was done, what worked and didn't, with a spectrum menu so people could quickly get information relevant to the type of thing that they wanted to do.

The camp movement, working in conjunction with other green groups that don't (yet) share a commitment to NVDA, could create enormous political (and economic) pressure on the governments and corporations meeting in Copenhagen.
Thousands of people could get involved in NVDA without having to risk arrest, or take a week's annual leave or travel to Copenhagen. That could create a very strong base for 2010 and beyond.

Are the key questions-
Where do we want to be in 2010, 2012?
What kinds of things do we want to see happening and by whom?
What kinds of things should be accepted as legitimate and essential by the mainstream?
How can a broad-based campaign of non-violent direct action make that happen, and how can a broad-based campaign of non-violent direct action best be accelerated?