Norwich's City Hall was hit by the 'yarn bombing' craze on Saturday morning.

A group calling themselves the Norfolk Ninja Knitters have taken credit for the woollen additions to City Hall.

Yarn bombing is a growing craze amongst knitters looking to have a bit of fun.

Also known as guerilla knitting, the trend is believed to have been started in Texas, America, in 2005 as a way of brightening up public spaces and the underground movement has spread across the world.

Bins and lamp-posts were targeted, as well as the famous stone lions outside City Hall. The colourful scarves initially placed there were removed on Saturday morning however.

An anonymous spokesman for the Norfolk Ninja Knitters contacted the Evening News to say: 'We are deeply upset that our hard work has been removed by the council, have they no sense of fun in the current climate?

'We decided to do this for the Norfolk and Norwich Arts Festival so this was not just a random attack, we demand that our work is returned!'

Examples of guerilla knitting have been spotted in Norwich before, when lamp-post and bus stop cosies have been discovered at the St Giles end of the Grapes Hill footbridge, in Chapelfield Gardens and Unthank Road.