Agatha Cackle is a major antagonist of the children's book series The Worst Witch. She is Amelia's evil twin sister who wants to take over the Cackle's Academy.

She is portrayed by the following actresses; Clare Coulter in the 1998 series, and the New Worst Witch, the late Charlotte Rae in the Telemovie, Clare Higgins in the 2017 reboot series, and Claire Gover as Young Agatha also in the 2017 series.


She and Amelia look almost similar in appearance (considering they're twins): they're both short, and wear gray, but Agatha has glasses that are large and round.


The Book Series

The Worst Witch

In Mildred's first year, on Halloween, Mildred spots her and her coven plotting to turn the whole academy into frogs.

In a flash of fear, Mildred turns both Agatha and her coven into snails and puts them in the boxes meant for the frog-pupils and frog-teachers and takes them up to the academy to show to Miss Cackle; Miss Cackle and Miss Hardbroom then deal with the witches.

The Worst Witch Saves The Day

Agatha reappears in Mildred's third year, where she sneaked into the school disguised as a new teacher, Miss Granite, with a high-pitched, squeaky voice, a huge cloud of orange curls, and an extremely bizarre personality. She is later found out by Mildred when Mildred comes to collect Tabby from her. Luckily, Mildred and her friends turn Agatha and her coven into snails themselves. While disguised as Miss Granite, Agatha is able to appear and disappear HB-style.

1998 Series

In Mildred's first year, on Halloween, Mildred spots her and her coven plotting to turn the whole academy into frogs.

One of Agatha's first instructions was to "Get Hardbroom" noting that she was the one they needed to get first because of her power. Mildred ends up shrinking the witches and handing them to Miss Cackle.

At the end of Mildred's First year, Agatha Sneaked into the Academy disguised as Miss Cackle, Mildred and company, however, realize that it is not Miss Cackle, but Agatha back to cause more trouble.

The girls track down the real Miss Cackle to the store cupboard in which Mildred and Enid were once trapped. Unfortunately, they are discovered by Agatha's two wicked cronies, Millicent Coldstone and Betty Bindweed. Mildred puffifies them and saves the day, for which she earns a raise in her final grade from C- to A+.

2017 Series

She reappears as a recurring character and the main antagonist of Season 1 of the 2017 series.

On Selection Day, Agatha turns up, and Miss Cackle gives her permission to speak to Miss Hardbroom for an internet article. Mildred then witnesses Agatha putting a spell on the celebratory meal. When Mildred tries to warn the staff, she is magicked outside the school grounds. With the help of a magic frog she levitates herself back into the school, where she manages to prevent Miss Cackle eating the soup, announcing Agatha put a spell on it.

Agatha invokes a section of the Witches Code and she and Miss Cackle have a magical duel. Agatha wins and turns Miss Cackle into a snail. After Miss Hardbroom pointedly drops hints (in Midred's direction) about how students or staff are bound by the witch's code and can do nothing about Agatha now being in charge, Mildred prompts the cat to knock the soup with Agatha's spell - which was a total obedience spell - over Agatha and then orders her to turn Miss Cackle back to normal. Agatha's powers are then confiscated.

In The Great Wizard's Visit, Agatha masquerades as Miss Cackle again, while. The real Miss Cackle is in an enchanted sleep on the bed. However, when Mildred's potion display gets out of control and The Great Wizard is splashed with potion, he announces that he will be removing Miss Cackle as headmistress, and the school will go to the next Cackle in line - Agatha. However Miss Hardbroom is able to talk him out of it with a speech in support of Miss Cackle.

In The Mists of Time, Mildred and Ethel accidentally go back in time, and meet Ada and Agatha as schoolgirls, and their mother Alma as headmistress. Agatha and Amelia try to take their mother's power and run the Academy themselves, however Mildred and the Miss Cackle from the present talk them out of it. It turns out Agatha is the eldest (by 13 minutes), not Ada as they believed, meaning that Agatha was supposed to inherit the Academy. Their mother told Ada that she lied about which twin was older as she wanted Ada to have the school, because Agatha would never run it according to the proper values.

Agatha ends up getting expelled and sent to Wormwood's Academy (where wicked witches are sent) while Ada becomes head girl. They apparently attempted to run the school together, but it was a disaster.

In Out of Bounds, Agatha escapes her banishment at Darkwood Cottage, and pretends to be Miss Cackle again. She claims Agatha has taken her powers and tries to get Mildred to give her hers, but Mildred realises that it's actually Agatha. Agatha and Miss Gullet then turn up at the Academy, and claim that Agatha is Miss Cackle. Esmerelda invites them in, and is tricked into giving Agatha her power.

In The Worst Headmistress, Agatha and Miss Gullet terrorise the school; they turn Miss Drill back from a snail, but turn Miss Bat and Algernon into frogs and Esmerelda into a trophy, while Ethel is made head girl. Agatha also casts enchantments so that no-one can use magic without her knowing. Agatha also turns The Great Wizard into a balloon, and traps Miss Cackle and Miss Hardbroom in a painting.

The students stand up to Agatha, saying that if Agatha is going to be Headmistress, they will all quit so she doesn't have anything to be Headmistress of, and everyone agrees. Agatha decides that if she can't have the school, then no one will, and casts a spell to destroy the castle. When Agatha tries to destroy the school, All the students chant together to stop her spell, and this also changes Esmerelda Hallow, the teachers, and the grand wizard back into themselves, and Agatha and Miss Gullet end up trapped in a painting by Miss Cackle.

In series 2, Miss Mould attempts to save her from the painting but Mildred Hubble convinces her to become good and Miss Mould's plan fails.

In series 4, Agatha returns again. In episode 12 (the Witching Hour Part 1), Agatha tricks Ethel into freeing her from the painting. In episode 13, Agatha pretends to be Ada Cackle (who had exploded) and claimed that she used magic to revive herself. She then proceeds to send all the students (except Maud, Mildred and Ethel) to a place called Vanishment, where they will be recycled on the Witching Hour. Agatha sends a voicemail to the Great Wizard telling him if that if he hands over his title to her, then she will free the students. However, her plan is foiled when Ethel retrieves the stones that Ada turned into when she exploded and Mr Daisy uses magic to turn the stones back into Ada. Just as Vanishment begins to recycle, the students escape. Ada tells Agatha that she must return to the painting. However, Agatha, noticing that she has been defeated for the final time, begins to chant the spell that sends her to Vanishment. Ada and HB both plead Agatha to stop but she continues, accepting her final defeat, Agatha is teleported to Vanishment, where she is instantly recycled, thus killing her.


  • Despite being evil, she's proven to be pretty intelligent at times, like in her first appearance, when she ordered Coldstone and Bindweed to take out Hardbroom: the most powerful witch in the academy. In her second appearance, she tried to eliminate Mildred as an enemy before her takeover, knowing that the girl would pose as a treat to her plans.
  • In all of her TV and film appears Agatha is played by the same actress, as her twin sister Amelia Cackle.
  • With The Worst Witch being often compared to Harry Potter as both are fantasy series centered on boarding school that teaches magic, written by British author among other things, Agatha can be equated to Lord Voldemort.
    • The plot of The Worst Witch contrasted Harry Potter, however; while the former centered on a normal girl who attended school of magic only to struggle to keep up with her more accomplished peers, the latter is a war story revolving the rise of a male legendary figure/Chosen One with immense power who forced to spend much of his youth in mundane environment until a set of circumstances unveiled his true nature and destiny as the champion of forces of good in the same vein with Star Wars.
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