The phrase "upper chamber" refers to a part of a legislature or governing body that has more power or authority compared to another section or chamber within the same system. Full definition
A committee will look into ways of creating a wholly or mainly elected upper chamber on the basis of proportional representation. (politics.co.uk)
The only promise there was to «establish a committee to bring forward proposals for a wholly or mainly elected upper chamber on the basis of proportional representation». (politics.co.uk)
We agree to establish a committee to bring forward proposals for a wholly or mainly elected upper chamber on the basis of proportional representation. (politics.co.uk)