* Law for Shura Council election ruled illegal
* But chamber to remain until new parliament elected
* One of many legal challenges to Islamist leadership
Egypt's Supreme Constitutional Court ruled as illegal the law by which the upper house of parliament was elected but said the Muslim Brotherhood-controlled chamber would not be dissolved until a new parliament is in place.
Sunday's ruling said the upper house, or Shura Council, would be dissolved once the new parliament convenes. A date has yet to be set for the elections which President Mohamed Mursi said could begin in October.
The ruling seemed likely to heighten tension between the Muslim Brotherhood and the judiciary over judicial reforms which the Islamists see as necessary to removing Hosni Mubarak-era appointees but judges see as a bid to purge their ranks.
The court also ruled as illegal the body which drafted a constitution that was approved in a popular referendum in December. The implications of that ruling were not immediately clear. Some legal experts say that the constitution itself is above legal challenge because it was approved by a popular vote.
The case against the upper house of parliament, brought by an independent member of parliament, follows a similar challenge that led to the dissolution of the Brotherhood-led lower house last year.
It is one of the many lawsuits, filed mostly by Muslim Brotherhood opponents, that have complicated the transition from Hosni Mubarak's rule after he was swept from power by a 2011 uprising.