It isn't rare but not necessarily something that happens a lot.Thank you so much, this is so helpful. I don't think there was any mention in my VS offer letter. I will be sure to check the contents of the TC offer letter when it arrives.
In your experience, is this a common situation to be in?
@aetheriius congratulations on your VS and TC offers! As @Jessica Booker says, there should be no negative repercussions doing what you are proposing, apart from leading the first firm to be unimpressed when you renege. Also, I should mention that I personally know multiple people who were very upfront with firms where they had TC offers and asked for permission to keep their offers open so that they could do later vac schemes in order to make a fully considered decision. I don't see any harm in asking the firm where you have a TC offer if they would be willing to allow you to do this, as the worst that could happen is they say no. I hope that helpsIt isn't rare but not necessarily something that happens a lot.
The other thing you could potentially do is explain to the TC firm that you have a VS coming up and would they consider extending the offer period until that scheme ends. However, if this TC is starting within the next 9 months or so, they might not be willing to do this because they are likely going to need to ensure the vacancy is filled.