Addressing the parliament on Wednesday, the British Prime Minister Theresa May conceded the possibility of delaying the UK’s exit from the EU in “exceptional circumstances.”

Theresa May did not specify the circumstances she would consider exceptional, but her concession is a step back from the demand for a fixed date of departure defined in the so-called Brexit bill.  

The date that was supposed to be carved in stone was March 29, 2019. However, there is now room for flexibility.  

The fixed date demand was advocated by Leave campaigners, such as Boris Johnson. But, this position is currently untenable since the government needs the support of moderate backbenchers who want more flexibility in negotiations with Brussels.

The British Prime Minister hopes to negotiate a transition deal by March 2018 and a long term trade with the EU by October 2018, just in time for its approval by national and regional parliaments. That will require Brussels’ agreeing to a “bespoke deal,” which does not appear likely.

The EU chief Brexit negotiator, Michelle Barnier, has made clear that Brussels cannot agree to “cherry picking” and an agreement that will entail access to the Single Market, including services, seems unlikely.

Theresa May talks about a two-year transition period to last until the end of 2020. Hardline Brexiteers are advising against the UK accepting rules and regulations from Brussels, preferring an earlier clean break.

For the European Commission “transition” means access to the Single Market but also free movement of capital, people, and goods. It also means European Court of Justice Jurisdiction and regular contributions to the EU budget. May’s government intends to avoid the dangers of “cliff-edge” for businesses, which is costing the economy a sudden drop in investment.

However, May’s government is facing pressure from Leave campaigners resisting the UK becoming an “EU colony” — in the words of Boris Johnson — and backbenchers wanting to avoid an economic crisis. The votes of both sections of the party are necessary to hold the government in office.