After being visited by small but dedicated teams of undercover children – and their parents – the Mansfield museum in Nottinghamshire has been declared the most family friendly in the UK.

It won the 2011 Guardian family friendly museum award from a shortlist that included the Abbey House museum, Leeds; the Corinium, Cirencester; the Horniman, south-east London; Kilmartin House, Argyll and the Potteries museum and art gallery, Stoke.

The local authority-run Mansfield museum's collection includes 19th-century porcelain and glass cabinets of stuffed animals.

One of the undercover judging families were Karla Lesingham, from Northampton, and her children Aidan, eight, and Nadia, five.

"She said her children enjoyed the dinosaur exhibits at Mansfield and also the activity trail, which uses a recycled junk character called Eco Dude. "The museum has a happy family feeling," she said. Aidan wrote in the visitor's' book that it was the best museum he'd ever been to.

The award was first given out in 2004 by a charity founded by occasional Guardian writer Dea Birkett after a drama at the Royal Academy when her two-year-old son was shown the exit for shouting "Monster! Monster!" at the Eagle-man statue. Birkett said: "The feedback about Mansfield was fabulous, they treated them as individual families and there wasn't a one-size-fits-all approach. Also, there was no sense of them thinking, 'we've got it right' and then sitting back on their laurels – they change things all the time, they take risks and are very playful.

"I love the fact that the local choirs are invited in to practise, it turns on its head this idea of museums being places for quiet."

The venues are judged against a 20-point manifesto drawn up by Kids in Museums, which includes demands that museums are height aware, and that attendants should never shush.