Is it customary to be reimbursed for travel to a PhD interview day? I'm applying for PhD programmes over in the UK and begun to get my first invitations for interviews. Some of them have to be in person as they include a tour of the facilities and such. Unfortunately, travel over here is not cheap and it got me wondering - is it customary for the interviewing institution to reimburse the cost of my travel?

On one hand the invitation emails do not mention anything about the cost of travel but on the other hand I got reimbursed even for travelling to my undergraduate interviews.
If the invitation did not specify that you'll be reimbursed, then assume that you won't.