COPENHAGEN — Greenpeace activists who gatecrashed a royal gala dinner at the December 2009 United Nations climate conference in Copenhagen and their helpers went on trial in the Danish capital Monday.

According to Copenhagen City Court documents, 11 activists face charges ranging from falsifying documents and number plates and claiming to be public officials to the rare offence of lese-majesty, or disturbing the peace of the monarch.

A Greenpeace spokeswoman told AFP the 11 had appeared in court and pleaded not guilty.

On December 17, 2009, the head of Greenpeace Spain, Juan Lopez de Uralde, and Norwegian Nora Christiansen fooled the Danish parliament's security by showing up for a gala dinner hosted by Danish Queen Margrethe II in a limousine and clad in evening attire.

Another activist, Christian Schmutz of Switzerland, posed as their bodyguard.

Once inside they unfurled banners reading "Politicians Talk, Leaders ACT" at the entrance.

The three were arrested along with a fourth activist shortly afterwards, and charges were filed against them earlier this year.

The two-day trial was not set to continue until after a summer break, on August 19, when the final verdict is expected.