From 1996 to 1999, Berrington starred alongside Emma Wray and Tony Robinson in the ITV comedy-drama 'My Wonderful Life'. In 1999, she played Marie Antoinette in Let Them Eat Cake, starring Dawn French and Jennifer Saunders. In cinema, Berrington has featured in many popular films such as The Little Vampire and, more recently, Nanny McPhee with Emma Thompson and In Bruges alongside Colin Farrell, Brendan Gleeson and Ralph Fiennes. In 2008 and 2009, a she played Mel in Moving Wallpaper. She was in the 2008 Poirot episode "Cat Among the Pigeons". Berrington also featured in the 1993 Mike Leigh film Naked. She also had a role in Leigh's 1996 drama film Secrets & Lies, starring Brenda Blethyn, Marianne Jean-Baptiste and Timothy Spall.

In 2009, Berrington and Actress Shirley Henderson were the stars of the popular ITV drama May Contain Nuts she played Ffion, a snobbish suburban mother. Berrington also played Nicola, a nurse in the BBC Two comedy, Psychoville. She also appeared as Food Technology Teacher Ruby Fry in the BBC TV series Waterloo Road from 2009 to 2011, departing after two series on the show. She played "Auntie" in "The Doctor's Wife", an episode in series 6 of Doctor Who. In 1997, she appeared in a TV Licence advert. In 2012 she was in an episode of New Tricks, playing a murderer called Grace. From 2012–13 she portrayed Paula Kosh in the Sky 1 comedy series Stella, in 2015 she returned for two episodes.

In 2011, Berrington starred in the BBC Christmas show, Lapland as Paula, a role which she reprised in the six-part spin-off series Being Eileen, which aired from February 2013. She appeared onstage in the 2013 play The Low Road. She appeared on Series 2 Episode 4 of Cuckoo as Sandra in August 2014.

In 2016, she appeared in "Hated in the Nation", the sixth episode of the third season of the Netflix original, Black Mirror.