May being encouraged to drop red lines

"May has ruled out staying in the EU’s single market, an option that is considered less economically damaging, because Britain would not be able to control immigration from the bloc. She has also rejected staying in a customs union with the EU."

https://uk.reuters.com/article/uk-britain-eu-major/former-pm-major-urges-may-to-drop-brexit-red-lines-idUKKCN1PD08K