A woman from Brighton has marked the first anniversary of her being mistaken by Donald Trump for his daughter on Twitter to voice her growing alarm about his presidency.

In an oversight by the then president-elect, the Twitter name of Ivanka Majic, a formal digital director for the Labour party, was added to a retweet intended to praise his daughter Ivanka Trump.

At the time Majic used the unexpected media attention to raise concern about the prospect of a climate change denier in the White House.

A year later, Majic has written a blogpost to condemn Trump’s record in office and to set an example to her own daughter on the importance of speaking out.

“When my tiny daughter is much bigger I want her to know that she has the right to speak to anyone,” she wrote. “A nonsense, clumsy, careless tweet gave me a megaphone … If you want people to hear what you have to say then you need to keep shouting.”

Majic admitted to initial hesitation about responding to Trump, but said she was bolstered by supportive messages from all over the world. Posters with her name on them appeared at the Women’s March against Trump in both Washington and London.

In her blogpost, Majic said Trump’s decision to withdraw the US from the Paris agreement on climate change showed the dangers of being “ignorant and powerful”.

But Majic also widened the scope of her criticism to include racist comments by Trump and his repeated taunting of the North Korean leader, Kim Jong-un.

“How is it that the most powerful man in the world gets to threaten nuclear annihilation as he pleases? He produces and shares hate speech. On what whim or trigger will the country I live in, or the one you live in, get called a “shithole” or get subjected to a travel ban?”

Majic also noted that Trump’s “careless” use of Twitter had inadvertently thrust more people into the limelight. Last November Trump mistakenly sent a tweet aimed at the British prime minister to a Bognor teaching assistant called Theresa May Scrivener.