This is the stuff if you want to brew an authentic English porter.
Just brewed a London porter (trying to clone Fuller's porter), with about 10% brown malt in the grain bill. The beer turned out very close, and I'm pleased. I don't think you can get the right flavor profile without brown malt.
I use this in my London Porter recipe. Unique tasting grain that can't be duplicated. Has a rich grainy, roasty, slight coffee taste that can't be beat. Roasty but not harsh. I like it so much in my Porter recipe that I use 10% for a sold punch of rich flavor. You can use less of course around 5% at first to see if you like it, or go for it and enjoy!