A serviced office operator off Commercial Street, E1, showed me a laminated colour chart on the cupboard door of every janitorial store across four buildings. Handsome thing. Four colours, clear pictograms, a supplier’s logo in the corner. In the store on the third floor of the Aldgate building, one blue cloth, twenty-two blue cloths in the drying rack, and a red one on the windowsill that had plainly been used to wipe a kitchen worktop, because it smelled of the same lemon degreaser as the worktop. The chart had been on that door for three years. Nobody had ever been asked a question about it, and nobody had ever been trained against it, and the operator had scored full marks on colour coding in two separate client audits.

Does any statute name the colours?

No. There is no line in English law that says red for washrooms and green for food areas, and any contractor who tells a client otherwise is overreaching.

The requirement arrives by a different route, and it arrives with real teeth. Retained Regulation (EC) 852/2004 obliges food business operators to keep premises clean and to put in place procedures based on HACCP principles, and cross-contamination between a toilet cubicle and a sandwich counter is precisely the hazard those procedures exist to control. An environmental health officer inspecting a café inside an office building in Paddington does not need a colour statute. They need to see a documented system that prevents the transfer, and colour separation is the system almost everyone uses because nothing else survives contact with a real cleaning shift.

Section 2 of the Health and Safety at Work etc. Act 1974 and the COSHH regulations do similar work in different premises. The duty is to control the risk. The colours are the method.

Where the requirement comes closest to being explicit

Healthcare. The national colour coding scheme published by the National Patient Safety Agency in 2007 was carried forward into the National Standards of Healthcare Cleanliness, and any premises delivering NHS-commissioned care in London is expected to follow it. Red for sanitary fittings and washroom floors, blue for general areas, green for catering and ward kitchens, yellow for isolation and infection control.

Private clinics, dental practices and occupational health suites inside commercial buildings inherit that expectation through CQC registration whether or not their landlord has noticed. A dermatology clinic on the second floor changes the specification for the whole floor.

Which scheme should a London office contract specify?

Name one. That is the entire recommendation, and it is the one thing most specifications omit.

The four-colour NHS scheme is the sensible default for mixed commercial use, because staff move between contractors and sectors constantly and it is the only scheme with national recognition behind it. A cleaner who worked at a hospital in Lewisham in 2022 and a hotel in Bloomsbury in 2024 has seen it both times.

Extend the scheme to everything that touches a surface, because cloths alone are half a system. Mop heads, buckets, wringers, squeegee sleeves, the handles themselves where budget allows. A red cloth used with a bucket that was last filled for the kitchen floor has achieved nothing at all, and bucket discipline is worse than cloth discipline in every operation I have inspected.

Single-use cloths solve the laundry problem and create a waste and cost problem in its place. They earn their keep in washrooms, in isolation cleaning, and in any building where the laundry loop has already been demonstrated to fail. For general office surfaces they are an expensive way of avoiding a management task.

What defeats a scheme is a client who writes “colour-coded cloths to be used” into the specification and leaves the definition to the contractor. Two contractors on adjacent floors of the same Marylebone building then run inverted schemes, blue and green swap meaning at the lift lobby, and the shared kitchen on the ground floor becomes a negotiation.

The yellow problem

Yellow means different things in different schemes. In the healthcare scheme it means infection control. In a good deal of hospitality and some catering suppliers’ literature it means washbasins and mirrors, splitting the washroom into red for the pan and yellow for the sink.

Both usages are defensible. Running both in one building is not. Pick the meaning, write it on the cupboard door, and reject any supplier’s chart that contradicts it.

Write the scheme into the contract as an appendix with the colours named against defined areas of the building, floor by floor where the uses differ. Two sides of A4. It survives a change of cleaning contractor, which a laminated poster supplied by a chemical company does not.

What happens to a scheme in the laundry?

It dies there, mostly.

Launderable microfibre only works if the loop is closed, and the loop is where the money and the discipline both leak away. Cloths go into a mixed bag. The bag goes to a contractor’s unit in Brimsdown, EN3, on a Friday. Everything gets washed together on one cycle because splitting four colours across four loads costs four times the machine time. Dye migrates, particularly from red. After thirty cycles the red cloths are pink, the blue cloths are grey-blue, and an operative under fluorescent tube light at eleven at night is making a judgement that the system was designed to remove.

Laundering separately by colour is the answer and it does cost more. Say so in the quotation rather than pretending otherwise.

Fading, bleeding and the temperature question

Thermal disinfection in healthcare laundry is conventionally taken as sixty-five degrees for ten minutes or seventy-one degrees for three minutes at the load’s core, and those figures get quoted at commercial cleaning contractors who have no clinical exposure whatsoever. For a general office, a sixty-degree wash with a detergent and no fabric softener is proportionate, and softener is the more important prohibition of the two because it coats split microfibre and kills its pick-up.

Retire cloths on a schedule rather than on appearance. A cloth that has lost its colour has lost its function regardless of how well it still wipes.

Why do schemes fail with the cloths still colour-coded?

Because the cloths were never the control. The control is a person deciding, on their fourth floor of the night, which bag to reach into.

Around one man in twelve has some degree of red-green colour vision deficiency, and the two colours carrying the highest consequence in every commercial scheme are red and green. Washroom and kitchen. The pairing that a substantial slice of the workforce finds hardest to distinguish is the pairing where the mistake matters most. This is a design flaw in the entire convention and the trade has quietly ignored it for twenty years.

The fix costs almost nothing. Buy cloths with woven-in text or a printed label. Use bins and buckets with moulded shapes as well as colours. Put the word on the cupboard door alongside the colour, in the languages your team reads, which in most London operations means English plus two or three others.

Red and green, and the eight per cent

Ask at induction. Not as a medical question, which it is not your business to record, but as a practical one: can you tell these two apart under the lighting where you will be working. Hand the person the two cloths in the janitorial store at night rather than in a bright meeting room at four in the afternoon.

I have had exactly one operative say no, at a leisure centre contract in south-east London, and he had worked in the trade for nine years without anyone asking.

How does an inspector or an auditor test it?

Not by looking at the chart. Environmental health officers in the London boroughs, when they are assessing a food operation inside a commercial building, score confidence in management alongside hygiene and structure, and confidence in management is where a colour scheme gets examined properly. They ask the operative. They ask which cloth goes where and what happens if the right colour has run out at nine in the evening, and the answer to that second question is the one that determines the outcome.

Client-side auditors following a BICSc-based framework do something similar. Storage separation gets checked, mop head allocation gets checked, and the laundry paperwork gets checked against the number of cloths on site.

Every serious failure I have seen came from the same root: a scheme that existed on paper and in the induction folder, with no consequence attached to breaking it and no supervisor present when it broke.

What ATP swabbing does and does not prove

ATP luminometers measure organic residue and return a relative light unit figure. They are useful for showing a kitchen surface is dirty and useless for showing it is safe, since ATP readings correlate poorly with microbial contamination and are affected by detergent residues and by the surface itself.

Swab before and after, on the same spots, and use the numbers to argue about method rather than to certify anything. A stainless steel prep bench at a staff canteen off Bayham Street, NW1, reading four hundred RLU after a clean tells you the cloth was carrying soil from somewhere. It does not tell you which colour that cloth was.

The chart in the Aldgate store came down in March and went back up with the four words printed underneath the four colours in eighteen-point type. The red cloth on the windowsill went in the bin.