Muslim in IB/PE London

I've worked in finance roles during and since graduating college - IB / PE internships and analyst & associate roles in buyside gigs (ignore the username). Worked the spectrum from MM to UMM to MF. Two caveats: a - worked in the US (this might be a net positive given the hardo culture here is typically more prevalent and less of a dense muslim population on the street or in general), b - mostly in mixed credit and equity roles, not pure control PE (tho hours across roles have been similar given we do opportunistic stuff too).

That said, never once had a problem across the board with observing Friday prayer throughout internships and/or full-time roles at any level, at any sized shop (if your concern is that culture varies between type of shop, size, buyside/sell-side, etc.). Be mindful of allocating a reasonable time to observing the prayer (i.e. I've always penciled out an hour for time it takes to drive and/or walk over, pray, and then commute back with a bit of a buffer built in if I for some reason get delayed), and don't take advantage of it to push back on work. Typically, I just have that 1 hour hold recurring weekly on my calendar and label it Friday prayer so people are aware that's exactly what I'm doing. Sometimes you may run into issues whereby an external meeting with Mgmt teams, 3rd party vendors, Sponsors, etc., may be scheduled that overlap with your prayer time but your associate should be ok with covering the notes for the call and/or can just ask someone to record and you can listen after and circulate notes. Obviously, the higher you get the more your availability matters if you're leading these calls and by that time people will respect that you have a hold on your calendar. As people mentioned above, you shouldn't have any issues, especially with drive towards diversity. Just make sure your work isn't effected.

Generally speaking, my advice, and understand that you may not have asked for it: be staunch in your beliefs and unwilling to compromise on stuff that matters. If someone pushes back on Friday prayer, that's not the type of person you want to be working for in the long term because they do not respect your personal boundaries. Now, I know people tend to say this stuff all the time - the "don't work for this type of firm" and most of the time I'm of the opinion that you just suck it up and take it - why the heck would you just give up working for a firm that you strived to be placed at for the last decade over having to put up with someones extra bs, or having a demanding boss, or working too much (within reason), etc.. But in this regard, when people don't respect your religious boundaries (Friday prayer, Eid days off, praying 5x a day in a separate space if youre that diligent, etc.) you gotta move. If you are practicing, you understand that religion comes first. 

Last point, from my experience, people in this industry generally like juniors with a bit of backbone both in and outside of work. For example, speaking up and defending their views on a deal or investment merit, but also on social cues like being uncompromising on their principals. I've actually been complimented by my colleagues for sticking to my religious beliefs like not drinking, praying, eating only zabihah, etc.

Hopefully that helps!