[4] Under Midland's ownership, Northern Bank shared its parent company's branding and the Griffin logo.

In 1986, Midland re-organised its British and Irish operations, and as part of this process it separated its Northern Bank branches in the Republic of Ireland and transferred into a newly formed company called Northern Bank (Ireland) Limited.

The first Danish branding was unveiled with new signage at the company's head office in Donegall Square.

Older banknotes bearing the Northern Bank name are still in circulation and continue to be acceptable for payments as they are gradually withdrawn.

Uniquely among sterling notes, this was a vertical polymer banknote, printed by the Canadian Bank Note Company (CBN) on Australian synthetic polymer substrate instead of paper, making Northern Ireland the only part of the UK to have issued a plastic banknote prior to Scotland & England issuing the £5 polymer notes in Autumn 2016.

[12] Most Northern Bank banknotes feature an illustration on the reverse side of the portico of Belfast City Hall, sculpted by F. W. Pomeroy.

The front of most notes depict a range of notable people associated with industry in Northern Ireland.

The designs currently in circulation are: Following the £26.5 million robbery in 2004 (see below), Northern Bank announced on 7 January 2005 that all its notes were to be recalled and reissued in revised designs and using the updated Northern Bank logo already used at the 10 pound note dated 2004.

The reissue began on 14 March 2005 and was scheduled to take one month; old notes remain exchangeable at branches of Northern Bank.

[16] The principal colours of Northern Bank notes of greater than £5 face value were changed with the 2005 reissue: On the older notes, the bank's N symbol was enclosed in a vertical rectangular bar above the 'Northern' logo; after reissue, the N monogram was presented as a free-standing hexagonal graphic above the new italic Northern logo.

On 20 December 2004 the cash centre at the bank's headquarters in Belfast was raided, and £26.5 million stolen.

The police and government as well as other major political figures in both Ireland and the United Kingdom accused the Provisional Irish Republican Army of being responsible.

On 9 October 2008 the trial of the only man to be charged with the robbery collapsed when Chris Ward, 26, was found not guilty.