Bulgarian rightist party Union of Democratic Forces will nominate former Speaker of Parliament Yordan Sokolov to run for a member of Bulgaria's Constitutional Court, according to reports.

A seat in the Constitutional Court remained empty when last Thursday Bulgarian President Rosen Plevneliev walked out just as controversial judge Veneta Markovska was about to swear in.

Markovska's name had become implicated in allegations of trade in influence, which she was unable to dispell, but nevertheless chose not to resign, after being elected to the Constitutional Court by Parliament.

After Plevneliev's move, Friday Bulgarian MPs decided to launch a new procedure to choose another constitutional judge from the parliamentary quota.

Monday Bulgaria's PM Boyko Borisov unexpectedly informally invited the Union of Democratic Forces to nominate a replacement for Markovska.

The move is interpreted as an attempt from the PM, who chairs leading Bulgarian GERB party to attract the allegiance of the Union and create further divisions in the feeble Blue Coalition between the UDF and Democrats for Strong Bulgaria.

The Union of Democratic Forces is expected to reveal its proposal Tuesday.

Yordan Sokolov was MP in Bulgaria's 37th, 38th, and 39th National Assemblies, and served as a speaker to the 38th, 1997-2001.

Sokolov is a respected Bulgarian expert in law, has published theoretical works in the area, and has a long practice as attorney.