Can someone post a link to the transcript where he said ‘tomorrow’?
He didn't, he said:
And the first step is a change of emphasis that we hope that people will act on this week.
We said that you should work from home if you can, and only go to work if you must.
We now need to stress that anyone who can’t work from home, for instance those in construction or manufacturing, should be actively encouraged to go to work.
And we want it to be safe for you to get to work. So you should avoid public transport if at all possible – because we must and will maintain social distancing, and capacity will therefore be limited.
So work from home if you can, but you should go to work if you can’t work from home.
Today was implied, because he then went on to say:
And from this Wednesday, we want to encourage people to take more and even unlimited amounts of outdoor exercise.
The BBC immediately afterwards stated that the return to work was from today. I'm not aware of any call from the government to say that was wrong.