Reading the previous reviews 6 years ago this bar definitely changed.
I was pleasantly surprised when I went to Prism. The Lower Ground Bar, was fun to be. Extraordinary cocktails, especially the Porn stars. They come with a champagne not cava as many other places would do. Friendly and knowledgeable bartenders with creative flare. Loved their bar bites, especially the prawns, not to mention the pitta bread with home made hummus.
Prism became my ultimate watering hole.

I must say, I came to Prism expecting it to be rubbish. I don't generally like London bars, finding them pretentious places full of people that have no idea how to enjoy themselves. This was great fun however! The crowd on the night I went (Thursday) is young and professional, without the normal arrogance that follows it, and very friendly. Bar staff are very competent, though not very friendly (it doesn't bother me; they were quick and efficient), DJ played some good music... only downside is the usual one of being expensive, but, having said that, it was no worse than any others around being just short of £7 for a double and mixer.
I will certainly go back to Prism again.

I've been to Prism for quite a few times now since they revamped it and I always had a good time there. The service is great (as you expect from Harvey Nichols) and the cocktails we had were lovely (they know their Old Fashioneds at Prism!). I also like the bar downstairs which is rather intimate and great for a date.

Prism is downstairs in the vault of the old bank of New York and has been very stylishly decked out with lots of luxurious trimmings. They have a very good wine selection and their signature cocktails are great.
Prism is a good place for a refined drinking experience.

Our visit to the cocktail bar in the basement of Prism during the early evening of 3rd March 2005 was a great disappointment. The score of 1 is made on the basis that 1 is of the lowest and 5 the highest standard. In all honesty a negative score is more appropriate for this location.

It was not unduly busy yet our party of 6 waited 30 minutes to receive the first of their cocktails ordered with the last person receiving their cocktail a full quarter of an hour later.

The waiter serving was awkward and shuffled between tables.

Not wishing to wait for such an undue length of time for subsequent cocktails we requested our bill. We had an inordinately long wait whilst the bar staff attempted to wrestle with this, how difficult can it be to total 6 x £7.50.

When the bill was finally produced, a service charge had been added and an expectant waiter eagerly looked for an additional(his personal tip.

Our opinion. GO SOMEWHERE ELSE when in the CITY. Go any where BUT Prism until they manage to serve cocktails promptly, with verve and a smile, then.

The standard of cocktail when finally presented - POOR.

The volume of music, on the loud side, conversation proved difficult.

Staff Attitude - Cocktail bar POOR; Cloakroom staff - GOOD.

Furnishings - Not what you would reasonably expect for a venue under the Harvey Nichols Group wing, more tacky lounge in Bristol than a premier venue in the heart of the City.