Typically there is also a promise to appear at the police station in order to be finger printed and photographed under The Identification of Criminals Act.
People very understandably, often take offence to having their finger prints and photographs taken. Regardless, make certain you attend to have them taken at the appointed time. If you do not attend you will be charged with failure to appear, for which the crown quite often seeks a jail sentence.
Once acquitted, you can ask that the fingerprints and photos be destroyed. However, the local police will keep records of your arrest on file forever.