Alliance Brexit spokesperson Stephen Farry MLA has said MPs should have already been well aware of the reasons for and the nature of the backstop.
Dr Farry was speaking following publication of the Attorney General's full advice regarding the UK's future arrangements with the EU.
"No one in Parliament should really be surprised or shocked at legal advice on the backstop. Its nature and purpose should have been evident to anyone following the negotiations over the past 18 months.
"The need for a backstop only arises due to the decision of the UK to leave the EU and the Government ruling out soft Brexit options around a Customs Union and the Single Market. Northern Ireland only works on the basis of sharing and interdependence. People and businesses work on the basis of both north-south and east-west interactions. Brexit risks new friction and barriers.
"The backstop is the minimum necessary to protect the Good Friday Agreement and to avoid a hard border. It needs to be there until and unless something better comes along. If there is a cut-off date or if it can be unilaterally broken, then the backstop is not a genuine insurance policy.
"The EU continues to be clear this type of backstop is integral to any Withdrawal Agreement, and it is wishful thinking to believe a different approach to withdrawal can be taken. The backstop was originally devised to cover Northern Ireland only, but it was the Government sought to extend this UK-wide.
"It does not interfere or undermine Northern Ireland's constitutional position and the Principle of Consent. Indeed, it may create some comparative economic advantages for this region. This reality should have been clear to all MPs before and should be readily understood now."