You cannot have your own cake and also eat it. The EU has always insisted that enjoying the full benefits of market membership can only come with an agreement to play by existing rules. In the UK, the last deal discussed, especially if UK cabinet unity is to be maintained, included promises of “frictionless trade”. But that may still end up looking a lot like temporary membership of the customs union. Come on Parliament drop the pretense and start working on real problems. If that requires a second referendum, so be it. Check out what the Guardian published on this https://www.theguardian.com/commentisfree/2017/aug/19/british-voters-second-referendum-on-brexit