Located at the back of Smithfields Market, this is the place to go for karaoke. You can hire a number of different sized rooms which range from around £100-250. A great night out with your friends and is open until around 4am (can close earlier if the venue is quieter).
Only tip I have is definitely do not bother ordering any food. All very expensive and the portions are small and food is bland. Just stick with the karaoke!