The Government has rejected the idea its plans for Brexit amount to an "affront" to the sovereignty of Parliament.
The case to appeal the High Court ruling that Theresa May must consult MPs before triggering Article 50 opened yesterday in the Supreme Court.
James Eadie QC, who is representing the Government, told the court today: "It is said that the Government giving Article 50 notice is an affront to parliamentary sovereignty because Parliament has created rights and only it can alter them.
"Our case fully respects, and offers no affront, to parliamentary sovereignty. Parliament does not seem to want the obligation the High Court has thrust upon them.
"Article 50 merely starts the process. It effects in itself no change in the law, the outcome can't be known.
"The aim will be to seek agreement. The negotiations will no doubt be long and arduous and Parliament will inevitably be involved in that process of withdrawal."
He insisted that were the Supreme Court to rule against the Government, the "courts would be imposing, in effect, a new control of the most serious kind in a highly controversial area."
The case is due to end on Thursday, with an announcement of the verdict given in 2017.