There is no specific power to split up groups of motorcyclists. The police and on certain roads Highways Agency traffic officers have a general power to direct a person driving or propelling any vehicle, including a motorcycle, to stop, proceed in, or keep to a particular line of traffic. It is an offence not to comply with such a direction. Exercise of the power to direct vehicles on particular occasions and in particular circumstances is an operational matter for the police and Highways Agency. It may be to reduce or prevent crime, to increase safety, or to regulate traffic.
Neither the Home Office nor the Association of Chief Police Officers has issued such guidance. Policing of roads is an operational matter for individual chief officers of police.