Q:

manager agreed on shorter notice, but conditionally until the end: is it common practice in UK?

My line manager agreed on halving the notice period.
However, she gave me an arbitrary list of projects and I must complete everything before the last day (one month). This agreement can be canceled at any time if the weekly review is not satisfactory, UNTIL THE LAST WEEK. This means that until the last end I won't be able to confirm the start date with my new employer.
My problem is not about the list itself (I might pull it off), but about the fact that there is a lot outside my control and I want to be sure that on day X I will start somewhere else.
I think that this is underhanded. Is this common or acceptable practice in UK?
(answers focused on UK employment practices)

A:

Ask yourself, is the new job in the bag. If so this helps.
A verbal agreement is a contract in UK law (as far as I understand). However it is difficult to enforce or prove. (http://www.harris-harris.co.uk/is-a-verbal-contract-worth-the-paper-on-which-it-is-written/)
So, if the job is in the bag we can be a bit pragmatic. If you leave at the verbally agreed time what could possibly happen:

They will not pay you. It is unlikely. You can take them to a small claims court and and reasonably sized company will not wish this to happen (you will win even representing yourself, they will have hassle and would have costs, perhaps bad publicity for arguing over a little money in there grand scheme of things)
They could sue you over breach of contract. Would it be worth their while. I assumed you have handed in some letter giving your notice that you are leaving and therefore going to be arguing over a few weeks. Their lawyers (if it even gets that far) would tell them not to bother.

So in summary - do the time that you agreed with. Try to end on good terms. It is probably a bit of posturing to get as much done in the final lap. Just keep a copy of the resignation letter and a note of the date/time of the verbal agreement. Perhaps talk to HR and get some written confirmation.
Best of luck

