edinburgh group anti-brexit scottish members parliament give go-ahead pursue legal action establish whether unite kingdom unilaterally stop process leave eu scottish court say friday scottish court session accept petition cross-party group seven mps exclude british prime minister theresa may rule conservatives determine whether brexit stop britain act alone decide reverse process british government three weeks respond challenge edinburgh court scotland supreme civil judicial body set date hear case spokesman say seven mps labour party scottish national party liberal democrats scottish green want court sessions refer matter european court justice eu high court conclusively rule issue know possible stay european union member state allow experts believe parliament withdraw leave notification without permission scottish mps say statement early week one way sure court decide article 50 mean may formally notify eu britain intention leave eu trigger article 50 lisbon treaty march 29 start two-year exit process say tolerate attempt parliament block brexit supporters argue last year referendum vote leave attempt halt process would anti-democratic opponents say country right pass final judgement exit deal negotiate scottish challenge late legal attempt try ensure happen article 50 specify whether exit process unilaterally reverse although former british diplomat lord kerr draft say britain change mind stage final exit date 2019. referendum saw 52 percent voters back brexit poll shake britain structure voters northern ireland scotland back remain eu wales england opt leave however recent bmg opinion poll find 51 percent britons would keep eu membership versus 41 percent still want leave legal action see whether uk could unilaterally stop brexit get go-ahead