She knew she had to come to conference with some more detail other than "Brexit means Brexit".
She knew she'd be pressed for more clarity on her timetable for our departure.
So Downing Street concluded Theresa May would have to announce something.
So we learn two things today: that our divorce proceedings with the EU (Article 50) would begin by the end of March 2017; and that all EU laws and regulations would have been enshrined in UK law at the moment we leave.
So a trickle of new information but not what you might describe as an avalanche.
But the reaction within her own party to those nuggets of new information illustrates the problem Theresa May has.
The former Cabinet minister and Leave campaigner Iain Duncan Smith told me that he'd be quite happy if Article 50 were triggered tomorrow - but, at the very least, the Prime Minister should do it as soon as Big Ben strikes midnight on January 1st.
However, the prominent Remain campaigner - and former minister - Anna Soubry told ITV News that the new date of March was "too soon" because there was still so much uncertainty over the UK's future trading relationship and access to the single market.
Too late or too soon? Hard Brexit or Soft Brexit? Leave on good terms or force an acrimonious divorce?
Those are the competing voices which are constantly ringing in Theresa May's ears.
Competing voices which also exist in Mrs May's own cabinet.
But there is one issue on which all Conservatives appear to agree: that the UK is leaving the European Union and Brexit will happen just as voters demanded it should.
Senior staff around Theresa May tell me there are no voices of disagreement on that issue.
Theresa May will not row back on Brexit, there will be no second referendum, she has no half-hearted approach to leaving the EU.
Downing Street aides have also tackled the criticism that Theresa May has no real plan and is not sharing her strategy with voters.
She will keep the public informed, they tell me, but only when she has something to say.There will be no running commentary.
So from now, right up to the moment the UK leaves the EU in Spring 2019, don't expect Theresa May to say very much.
As we are coming to expect from this Prime Minister, she will only speak when she has to.