Notable pupils included Andrew Cheung, Chief Justice of the Court of Final Appeal.

[citation needed] In 2002, when the Hong Kong Government wanted to alter the existing Article 23 concerning treason and sedition, Eu, with some other notable members of the Bar, including Alan Leong, Margaret Ng, Ronny Tong, formed the Basic Law Article 23 Concern Group.

Before the draft Bill became public, Eu put forward strong opinions and statements opposing certain measures of the Article 23 legislation.

[citation needed] Concern started to grow among Hong Kong residents later about Articles 45 and 68 of the Basic Law in 2004.

[citation needed] Eu ran for the 2004 LegCo election for the Hong Kong Island constituency in the same ballot as Cyd Ho from The Frontier.

[citation needed] Eu was the founding leader of the party, and held the office from 19 March 2006 to 8 January 2011.

[citation needed] In the debate over the Hong Kong government's 2009 reform package (referred to by government as the '2012 constitutional reform package') she was among the firmer voices in the pan-democratic camp, supporting the January 2010 resignation by five pan-democrat Legislative Councillors to force a by-election in which they re-stood (and were re-elected), intended as referendum on democracy.