It's bloody good.
Opp. "Good is it".
Var. Any adjective followed by an indicative of "be" (e.g., is, are) or a verb/action followed by an auxillary verb such as can, could, will, would, etc. following by a pronoun (e.g., it, they, he, she, I, you) means that the subject referred by the pronoun is NOT the adjective or cannot apply the verb.
To specify the object, this may be appended to the statement separated by a comma.
Opposite usage, using negatives: See example of how "not" can be used to indicate the way something IS.
1. "Small are they, your balls" - Baz referring to the size of Jay's bollocks because they are big.
2. "Shag us would they, them birds" - Baz referring to some girls in a nightclub that he thinks we wouldn't be able to pull.
3. "Not pissed am I not" - Jay fucking wasted.