The borough council's planning committee was discussing highly controversial plans to build 900 homes and widen a road through woodland in Titnore Lane, Durrington, Worthing.
The intervention began after meeting chairman, Tory John Livermore, refused to take any more questions from the public at the packed hall, which was being used as an emergency council chamber because of the massive local interest.
While security staff ejected one protester, others occupied the stage, unfurling a large banner and forcing councillors to flee. Police eventually removed all the protesters from the hall, after a half hour interruption, while chanting continued outside the front doors. There were no arrests.
As expected, the committee eventually gave outline permission for the development, though it may well be called in for a public inquiry.
And, of course, those meddling protesters have pledged to fight it every inch of the way.
Crunch day is approaching in the battle to save the last piece of greenfield and ancient woodland in Worthing, West Sussex. After years of delay and massive public opposition, Worthing Borough Council is preparing to give the go-ahead to the plans for a 900-home estate on land at Titnore Woods. In typically devious form, the council has avoided publicising the meeting - this Friday, June 10 - until the very last minute to try and stop opponents mobilising.
But supporters of Protect Our Woodland! - the campaign set up by local people to fight the plan - are calling on all those who support their fight to rally outside - and inside - the crucial meeting, which they fear will be nothing but a rubber-stamp for the developers.
The council planners meet at Worthing Assembly Hall at 6pm and POW! is urging protesters to be on the steps at 5.45pm to show their anger.
Said a spokesman: "We will be picketing the entrance to the meeting and hope to muster a strong and noisy presence inside. But because of the short notice we really need all those who sympathise to make an effort and support us."
People are urged to bring placards and banners etc as press will be there.
A message from POW! to its supporters said: "As many of you will know this development, if approved, will be built on the last remaining area of green field in Durrington, worst of all it will have a major impact on the unique Titnore ancient woodland and historic Titnore Lane.
"As this is possibly the only chance we will have to directly influence the council's decision on this scheme, it is of the utmost importance that everyone, yes everyone attend that meeting, the Assembly Hall must be full to bursting.
"Please bring your friends, and forward this message on to everyone in your address book and if possible post on websites."
Protest at 5.45pm, Friday June 10, Assembly Hall, Stoke Abbott Road, Worthing.