***Tricky situation with resigning for lateral move***

I was wondering if anyone could please provide advice given this particularly tricky situation.

To give some background, I currently work at a large-sized European bank that I think is safe to be called tier 2/3 (think RBS, SocGen, DB), in London. I have spent 1 year here and am now effectively Analyst 2. Below is the timeline of events that have happened:

• December 3: I find out about an internal lateral industry team position (Analyst 2) that I was interested in, and apply. HR tells me that they will arrange an internal interview soon.

• December 6: I get a linkedin message from a experienced hire HR person at Tier 1 BB (BAML / JPM/ MS) about several experienced analyst positions in industry teams that are available. Having not heard back from the internal team and obviously this one being the better opportunity, I apply as well.

• December 9: I get an interview and finish the interview with the Directors and MDs at my bank, at this industry team. They give positive signals.

• December 10-12: I hear back from the HR person at the Tier 1 BB, saying that I am invited for an interview. Given that this is a lateral position, they try to bundle the interviews as much as they can. I talk to 5 people on the 10th and 3 people on the 12th. They tell me they want to finish the recruiting process before Christmas (for obvious reasons) and will let me know asap.

• December 16: HR from my bank calls me and congratulates me fore getting the internal position in the industry team. She walks through next steps and tells me changes to the contract etc. One thing that catches my eye is that the notice period will be changed from 1 month to 3 months, should I sign the new contract.

• December 18: I hear from the Tier 1 BB that I got the position. Due to the 'Labour market test' to sponsor my Tier 2 working visa (change in employer), they have to delay the formal offer until 15 January (the job has to be advertised publicly for a certain number of days).

Now I am at a position where HR in my current bank can send the new contract for me to sign anytime, but when I sign the contract I will effectively have to let go the Tier 1 BB position that I obviously prefer because the new notice period will mess up the whole timeline for the Tier 1 BB onboarding. I am quite sure that my bank will send me the new contract before the 15th of January, which means that I will have to decide between 1) delaying the signing for some reason and 2) giving up the Tier 1 BB position.

However, 1) will be really hard since obviously I applied to the position wanting to join, and it will look bad if I suddenly become hesitant to sign the contract. HR also knows that this is a sector that I really wanted to join, since I have talked to them many times about this. HR therefore might think that I am considering other options, which is not good if, for some reason the Tier 1 BB offer faces some trouble (problems with visa process, last minute changes, whatever). The position is firmly secured as I heard from HR and who will be my new line manager, but in principle nothing has been signed yet so there is some element of uncertainty. 2) is obviously what I would never want to do.

What would you do? Would you just bite the bullet and find ways to delay the process as much as I can in my current bank even though it will reflect really bad on me? Or would you just go ahead to tell HR that I don't want to sign because I have another discussion ongoing, and wait until 15 Jan? Just quit before 15 Jan, hoping that the Tier 1 BB offer doesn't face any problems? Any other views?