I suppose, the (rhyming): nose
Source: LS3

I wudden mind: Yes, please.
Source: LS1

I wanna: I require a...
Source: LS1

I suppose (rhyming): the nose
Also: bugle, hooter
Source: LS3

Ibrox Park: soccer field in Glasgow where two major disasters occurred, one in 1902 when a stand collapsed, resulting in 26 dead and hundreds injured; and in 1971, when 66 fans died in a crush.
Source: GTH

Icers: ice cakes (i.e., with icing)
Source: Shaw III

Ickey, ther firebobby: the fireman. Some describe Icky as a mythical Lancashire personality. He is invoked mainly to engage the fancy of  children as the cause and blame of routine inconveniences and mysteries, something like "the little man who wasn't there."
Cf. "Da Ba" on this list.
Source: LS2

Iddle:It will.
Source: LS1

identity parade: a police lineup
Source: SL

Ignorance: typically refers to bad manners
Source: Shaw

Ikey. Yer very ikey. You are very dandified.
Source: LS1
flashy, overdressed, "posh"
Source: Shaw GS

Im. My husband(slightly derisive).
Source: LS1

imps: minute squares of liquorice, strong enough to seem to burn the tongue, but loved by children in the fifties. The candy was something like the Sen-Sen sold around the same time in the United States.
Source: SL

in a tick: momentarily
Source: SL

In der club. I tink I'm in der club, doctor: I think I am pregnant, doctor. See also" in the duff" and "in the pudding club."
Source: LS1

Inch and a Half(rhyming): scarf
Source: LS3

infernal combustion: Liverpudlian for internal combustion
Source: PL

Inny, the: The Liverpool Institute High School for Boys
Source: MMWB

Intensive Care Unit: the punishment block of a prison
Source: LS4

invisible blues(obsolete): plainclothes policemen
Source: LLMI

Irish Fever, the: the name often given to the typhus epidemics of the last century as it showed up in the paths of the famine migrations. Other names for it: gaol fever, spotted fever, camp fever, putrid fever.
Source: B47

Irish Guards Band, the: a bunch of scousers lined up with mouth organs
Source: BLH

Irish Takeaway: sardonic term for an abortion clinic
Source: SL

Irish Jig (rhyming): wig
Source: LS3

Irish confetti. A cargo uv Irish confetti. A cargo of stone chippings.
Source: LS1

Irish cattle: pigs
Source: Shaw ML

Itchy powder: lice. A euphemism derived from an irritant powder sold by joke shops.
Source: LS2