A cross-community vote taken during a late sitting of the Northern Ireland Assembly last night secured a victory for Mr Trimble and Mr Mallon, who had tabled a controversial amendment to a motion which proposed the setting up of a committee to scrutinise all aspects of their work.
The First and Deputy First Minister proposed the amalgamation of two committees, established last week on equality and European affairs, into one committee which would be given a further 10 areas of their business to scrutinise.
However, members of the DUP, Sinn Fein and the smaller parties argued that the central office also had the remit for 13 additional issues which would be left unscrutinised.
Speaking in favour of the original motion which envisaged more scope for the committee, the DUP deputy leader, Mr Peter Robinson, said Mr Trimble and Mr Mallon should allow themselves to be scrutinised to the same extend as other ministers.
The Sinn Fein MLA for Newry and Armagh, Mr Conor Murphy, said he was surprised at the amendment to amalgamate three committees into one. "The suspicion that they do not want property scrutiny of their department is very hard to avoid at this stage," he said.
Mr Trimble said the motion, as amended, allowed for the significant functions of the central office to be examined by a committee in a more rational and coherent basis.