How do you make good traditional English "builders style" Tea for a large group of people?

Problems with existing solutions

1. Tea bags, hot water and making it yourself method SUCKS
2. Tea urns can stew tea and be difficult to clean

Research

I am going to ask as many caterers and those who know about tea how it can be done. I'll also ask around the Internet. I am confident this problem can be tackled in an 'opensource' fashion.

I am sure the Indians or Chinese or the Russians with their Samovars must know.

Original idea