- Classifications
- Machine Shops
- Machine Tool Accessories and Services
- Machine Tool Merchants
- Machine Tools Sales
- Machinery
- Machines Special Purpose
- Magicians Supplies and Equipment
- Magnets
- Mail Order and Catalogue Shopping
- Mailing Houses
- Mailing Machines and Equipment
- Make Up Artists
- Management and Business Consultants
- Management Training
- Manhole Covers
- Manned Guarding
- Manufacturers Agents
- Manufacturers General
- Maps and Charts
- Marble and Granite Services
- Marinas and Boat Moorings
- Marine Electrical and Electronic Equipment Manufacturers
- Marine Electrical Services
- Marine Engineering Equipment Manufacturers
- Marine Engineers
- Marine Equipment
- Marine Services
- Marine Surveyors
- Market Gardeners
- Market Operators
- Market Research
- Market Stall Builders
- Marketing Services
- Marking and Identification Equipment
- Marquee Manufacturers
- Marquees and Tents
- Martial Arts Instruction
- Materials Handling Equipment
- Maternity Wear
- Mats and Matting
- Measuring and Analysing
- Measuring Instruments
- Measuring Machines and Systems
- Meat
- Meat and Meat Products Wholesale
- Meat Production and Preservation
- Mechanical Engineers
- Mechanical Handling Engineers
- Mechanical Handling Equipment
- Mediation
- Medical and Dental Laboratories
- Medical Equipment Maintenance and Repairs
- Medical Equipment Manufacturers
- Medical Equipment Rental and Leasing
- Medical Goods and Services
- Medical Instruments Manufacturers
- Medical Insurance
- Medical Waste Disposal
- Mediums
- Meeting Rooms
- Members Of Parliaments
- Membership Organisations
- Menswear Hire
- Menswear Retail
- Mental Health Centres
- Merchant Banks
- Metal Detectors
- Metal Finishing Equipment
- Metal Finishing Services
- Metal Merchants
- Metal Pressings
- Metal Production
- Metal Spinners and Pressings
- Metal Workers
- Metals Ferrous and Non Ferrous
- Metals Mining
- Meteorological Instrumentation
- Meters
- Metrology Equipment
- Mezzanine Flooring
- Microfilming Services
- Microwave Ovens
- Military Equipment Dealers
- Mill Shops
- Millinery
- Milling and Turning Services
- Mills and Millers
- Minerals and Ores
- Mini Buses Hire and Leasing
- Mini Cabs
- Mirrors and Decorative Glass
- Mobile Homes
- Mobile Phone Repairs
- Mobile Phones
- Mobility Equipment
- Model Makers
- Model Shops
- Modelling Agencies
- Money Transfers
- Monitoring Equipment and Systems
- Monumental Masons and Sculptors
- Mortar Manufacturers
- Mortgage Brokers
- Mortgages Commercial
- MOT Testing Centres
- Motor Caravan Dealers
- Motor Cycle and Scooter Dealers
- Motor Cycle and Scooter Manufacturers
- Motor Cycle Breakdown and Recovery Services
- Motor Cycle Breakers and Dismantlers
- Motor Cycle Hire and Leasing
- Motor Cycle Parts and Accessories
- Motor Cycling Instruction and Testing
- Motor Factors
- Motor Sports
- Motor Trade Insurance
- Motor Vehicle Dealers
- Motor Vehicle Leasing and Contract Hire
- Motor Vehicle Main Dealers
- Motor Vehicle Servicing and Repairs
- Motor Vehicle Spare Parts and Components
- Motoring Organisations
- Mould Makers
- Multimedia and Electronic Book Publishers
- Museums and Preservation Societies
- Mushroom Growers and Packers
- Music and Dance Schools
- Music Management and Promotion
- Music Publishers
- Music Shops
- Music Teachers
- Musical Instrument Repairs and Servicing
- Musical Instruments and Accessories
- Musical Sheet Music
- Musicians and Composers
