The following is from the Hinckley & Bosworth Borough Council website
Anyone walking a dog must pick up any fouling and dispose of it correctly. You should always carry bags to put the waste in, then you can either take it home to dispose of, use dog waste bins, or even a litter bin.
It is an offence to allow your dog to foul in any public place and not clean it up. The fine for this offence – Breach of Public Spaces Protection Order – is: £100 (reduction for early payment if paid within 14 days: £80) (S67 Anti-Social Behaviour Crime and Policing Act 2014).
The council can also issue a fine if a witness statement is provided by a member of the community. Reports must be passed to the Clean Neighbourhoods Team to investigate. In nearly all cases the witness will remain anonymous whilst action can be taken against the offenders.
It is not a defence to claim that you had nothing with you to clean up the mess.
The law does not apply to guide dogs for the blind.