Ms Waters, a former Ukip leadership contender, was also the deputy leader of Pegida UK – a far-right, anti-Islam organisation she helped launch with Robinson.
In a video posted last year, Ms Waters called for a freeze on immigration for five years and pledged to “campaign to bring the entire European project down for good”.
Ms Westley, a former campaign manager at the TaxPayers’ Alliance who entered Downing Street this week in Mr Johnson’s new administration, described Ms Waters as a “hero” in a 2016 post on Twitter, which has now been deleted.
Ms Westley had also called for the far-right activist’s work to be published, linking to a blog post by Ms Marie Waters.
In the post, Ms Marie Waters wrote: “I will show how Islam is bringing horrors to the west that are unprecedented in modern history. It has injected our civilisation with poison – this poison is particularly potent for girls and women and anyone who demands the right to freely express an opinion.
“Islam is dragging the free west in to a nightmare and I will prove it.”
Downing Street declined to comment on the posts. A friend of Ms Westley, however, told The Independent: “She recognises and regrets what is an ill-judged tweet and does not support or endorse the views of Ms Waters.”
They added she had made this clear when challenged on the same post last year.
But Labour’s Jon Trickett, the shadow Cabinet Office minister, said: “It is profoundly shocking that someone who holds these views should be at the heart of government. She should never have been appointed in the first place and Mr Johnson must now move swiftly to dismiss her.”
The campaigns director of Hope Not Hate, Matthew McGregor, told The Times: “Anne Marie Waters leads a far-right party with virulent Islamophobia at its core.
“If Waters now has someone who called her a ‘hero’ at the heart of the No10 operation it would be chilling. Downing Street has serious questions to answer.”
The Independent has approached Ms Westley for comment.
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