Not a lot happened in the UK yesterday - not really. We think it is best to ignore the new centrist party because it will not affect Brexit one way or the other, nor do we see any evidence of a groundswell of public support. When one of the new Conservative members of the now 11-strong independent group used the occasion to emphasise her support for fiscal austerity, politics as usual returned. The honeymoon period - or rather the mourning period - ended on the second day of this new group. 

After the three defections, the effective Conservative majority is now 323 to 318 votes. Dominic Grieve, the former attorney general, said last night that he too would resign from the Tories, but only if the government proposes to leave the EU with no deal.

If that were the case, he would not be the only one. So one of the firmer conclusions we draw immediately is that, if the Tories wanted to pursue a no-deal Brexit, they would need to have elections first. The reverse order makes no sense - elections in the middle of no-deal chaos.

So, where are we now? Theresa May's visit to Brussels yesterday yielded no concrete results - unsurprisingly. The technical talks will continue, but no agreement is expected by next week. The Sun reports that ministers want May to commit to an extension in case of no deal, or else she will see ministers supporting the Cooper amendment. We think this is a promise she can easily give. The Cooper amendment might still pass, as there is more support for it now than three weeks ago. But the amendment has lost much of its political significance. Back then, it was regarded as a proxy for a second referendum. This is no longer so.

Here are our three main Brexit scenarios:

• May brings a new deal mid-March. Deal passes. Government fast-tracks ratification. UK leaves on March 29. 
• no agreement until final marathon at or around EU summit on March 21-22. Meaningful vote delayed until end March. Deal passes. Short technical extension;
• Meaningful vote fails in either of the two scenarios. At this point elections are very likely.

What about the Cooper bill? If the meaningful vote is lost, it would force the government to make an official request to extend the Art. 50 deadline (preceded by a symbolic vote on whether the parliament actively supports a no-deal Brexit). It is possible that EU and UK agree a different period than the one specified in the bill. The EU is also free to attach conditions. 

Does the government have the ability to frustrate the Cooper bill? The bill is well-drafted and has no obvious loopholes. But it is not a fail-safe mechanism either. The government could: 

• ask for a short extension before bill takes effect, which would supersede Cooper;
• Cooper takes effect, meaningful vote is lost. Parliament forces elections. May would request short extension, Cooper bill mechanisms would be superseded in that case too;
• House of Lords filibuster to delay introduction of the bill until after meaningful vote;
• government could try to take legal action against the bill, or simply refuse to act on it, and deliberately cause a constitutional crisis;
• or it could co-opt the EU to frustrate the bill, either by trying to organise a veto of a single member state in the European Council, or to frustrate it in the negotiations with the European Council;
• we are, for now, disregarding more extreme measures such a prorogation or other means that would involve the Queen in her role as head of state.

It will probably not come to any of this, but this list may still constitute a useful warning to anybody who believes that Cooper is a fail-safe mechanism towards a Brexit reversal or a second referendum.