In July 2012, Morse's contract was not renewed, but she was not immediately written out of the series and continued to make occasional appearances until 21 January 2016.

Much of Mo's time is spent selling poor quality stolen goods and she trades with Fat Elvis (Shenton Dixon).

Mo attempts to sell Lucas Johnson's (Don Gilet) bibles to the public, as gruesome souvenirs of the killer.

When Kat goes into labour, Mo delivers her son, Tommy Moon, on the floor of The Queen Vic's barrel store.

When Mo learns that her old enemy, Pat, is terminally ill, she visits her in hospital and they end their long-standing feud.

Her suspicions are confirmed, when she discovers that Alfie is allowing Roxy Mitchell (Rita Simons) to stay in The Queen Vic.

Mo returns to collect rent from Kat, Michael Moon (Steve John Shepherd) and Alice Branning (Jasmyn Banks).

Mo is delighted when Kat and Alfie's twins, Bert and Ernie Moon (Freddie and Stanley Beale), are born, but the family's joy is cut short when a fire starts at their house and when it reaches a supply of knock-off hairspray, which Mo had intended to sell, a huge explosion destroys everything that they own.

Kat is badly injured and Mo is wracked with guilt, briefly moving in with Masood Ahmed (Nitin Ganatra), before taking an extended holiday in Lanzarote with Charlie.

Mo returns to Albert Square and is shocked to discover that Alfie and Kat have, once again, separated and that her family are financially struggling.

Mo reveals to a destitute Kat that she inherited money from her deceased uncle, Harry Slater (Michael Elphick), who had raped her as a child, impregnating her with Zoe.

At their leaving party, Mo shows a stunned Kat an engagement ring, revealing that she has accepted a marriage proposal from her long-time business associate and romantic interest, Fat Elvis.

When Kat learns she had also given birth to a boy along with Zoe, she realises that Mo knew about the secret, so angrily demands the truth from her.

After attending Charlie's funeral, Mo moves to Kent to live with her other granddaughter, Belinda Peacock (Carli Norris), as Kat cannot forgive her for having her son adopted.

Kat suddenly returns to Walford in a cab and is confused that The Queen Vic is holding a benefit night in memory of her and she is annoyed with Mo when she learns the truth, but is forced to hide in a cupboard when Ian visits with the raised money.

Mo claims to have psychic abilities as a trick to make money but in reality, she is listening into people's conversations with recording devices.

Kat starts a cleaning business with Jean and Stacey, and Mo is forced to join them, but she does not work hard and steals from the employers.

She returns briefly a year later when Stacey and Martin visit Mo and Jean at her campsite in Essex and for Kat's wedding to Phil Mitchell (Steve McFadden).

Mo teams up with Kim Fox (Tameka Empson) and Stevie's daughter-in-law Nicola Mitchell (Laura Doddington) to make an adult calendar of the men of Walford.

The family consisted of, grandmother Mo (Laila Morse), father Charlie (Derek Martin), his four children, Lynne (Elaine Lordan), Kat Slater (Jessie Wallace), Little Mo (Kacey Ainsworth), Zoe (Michelle Ryan), as well as Lynne's boyfriend Garry Hobbs (Ricky Groves).

[4] The character of Mo and the rest of the Slater family were created during workshops with Tony Jordan and John Yorke.

As the elder stateswoman of the Slater family, she's had her fair share of battles and she'll fight to the death to defend her girls.

Unless they cross her palm with silver – or any form of currency really.Mo's main link to the square is her former sister-in-law Pat Evans (Pam St Clement).

There is animosity between the two as Pat believes that Mo cheated on her late brother, Jimmy (Alex King) and still holds a grudge.

On Mo's return to the square, she stokes the flames on her long-running argument with Pat, which began three decades earlier.

[13] Morse's contract was not renewed in July 2012, but she was not immediately written out of the series and continued to make occasional appearances.

[16] On their reintroduction, Yorke commented, "It has been a real joy to find a way to bring them back together and we're incredibly excited about where we are taking them next.

[18] It was announced on 28 February 2024 that Mo would return full time to the soap in the Spring alongside her great-grandson Freddie.

"[21] Another writer for the Sunday Mirror, Paul Scott said: "As Big Mo Slater she is the battleaxe from Hell whose tongue-lashings have even the hardest of Walford's hard cases running for cover.

[24] In 2020, Sara Wallis and Ian Hyland from The Daily Mirror placed Mo 39th on their ranked list of the Best EastEnders characters of all time, calling her a "salt-of-the-earth Cockney chancer" who can "always be relied on for a laugh, involving an anecdote about her lover Fat Elvis".