Skip to content Skip to menu

Operation of the Mersey Tunnels

The Mersey Tunnels, approaches and marshalling areas are operated under the supervision of the Mersey Tunnels Police under the associated tunnel byelaws: The Mersey Tunnel Kingsway and Queensway Byelaws in effect at the time.

A key part of these byelaws is the control and regulation of vehicles carrying hazardous materials (as prescribed by the UN Model Regulations for the Transport of Dangerous Goods and the Agreement Concerning the International Carriage of Dangerous Goods by Road – ADR), which give detailed information of the classification of dangerous goods and any restrictions on passage through the Mersey Tunnels.

The legal obligation for complying with the dangerous goods legislation is the sole responsibility of the road haulier and all vehicles subject to these restrictions will be required to make a declaration before entering the Mersey Tunnel.

The authority will apply additional operating measures designed to reduce the risks related to vehicles subject to these restrictions using the Mersey Tunnel and may require passage under escort by a designated accompanying Police vehicle and may also prescribe additional restrictions and instructions.

Tunnel Designations and Tunnel Code Explanation

The Mersey Tunnels are classified as Tunnel Category D under the ADR Agreement on the International Carriage of Dangerous Goods by Road (2021), and the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2009.

In the UK and Europe, tunnels are allocated a category ranging from A (where there is no restriction on any dangerous goods) to E (where a limited number of dangerous goods are permitted without restrictions on passage). 


Tunnel Catergory Restriction
A No restrictions
B Restriction for dangerous goods which may lead to a very large explosion
C Restriction for dangerous goods which may lead to a very large explosion, a large explosion, or a large toxic release and dangerous goods restricted in tunnel category B
D  Restriction for dangerous goods which may lead to a very large explosion, to a large explosion, to a large toxic release, or to a large fire and dangerous goods restricted in tunnel category C
E Restriction for most dangerous goods and any carried in Limited quantities above 8T


Under the above scheme, all goods marked as being restricted for transport through tunnels of Category A, B, C and D are subject to restrictions through a Category D tunnel.

To assist in understanding specific requirements for the different hazardous substances/articles, each can be assigned a Transport Category and Tunnel Code, as exampled:

Transport Catergory →  1(D) ← Tunnel Code

The Tunnel Code determines whether the goods are restricted in the Mersey Tunnels or not, and the Transport Category can be used to identify the quantity of goods which are exempted from restriction.

A number of possible Tunnel Codes are used to specify both the nature of restriction and, in some case, a quantity at which the restriction comes into effect.

Possible Tunnel Codes on the Transport Document (accompanying paperwork) are as follows:


B Prohibited in Mersey Tunnel
B1000C Prohibited in Mersey Tunnel
B/D Prohibited in Mersey Tunnel
B/E Tank Only Prohibited in Mersey Tunnel
C Prohibited in Mersey Tunnel
C5000D Prohibited in Mersey Tunnel
C/D Prohibited in Mersey Tunnel
C/E Tank Only Prohibited in Mersey Tunnel
D Prohibited in Mersey Tunnel
D/E Bulk & Tank - Prohibited in Mersey Tunnel
E Allowed in Mersey Tunnel
- Passage allowed through all tunnels


The carriage of goods is separated into 3 types in the dangerous goods regulations – Packages, Bulk and Tanks, with the following prohibitions.

Prohibited in Mersey Tunnel: No goods showing this tunnel code are permitted.

Tank Only Prohibited in Mersey Tunnel: This would allow the travel of both packaged and bulk transport.

Bulk & Tank - Prohibited in Mersey Tunnel: Package transport is allowed through the tunnel.

Any goods with an E or (-) Tunnel Category are allowed in the Mersey Tunnels.

Tank Carriage and Road Tankers

Where tank carriage is prohibited this includes empty tanks/tankers, unless specifically cleaned or degassed.  When they are cleaned all vehicle markings must be removed or covered, with a 15-minute fire engulfment covering.

Key Definitions

The following simplified definitions will be of assistance in the application of the correct restrictions transported goods. Full details of the definitions are given in the full ADR document itself.


"Package" means the complete product of the packing operation, consisting of the packaging, or large packaging, or IBC, and its contents prepared for dispatch. The term includes receptacles for gases as defined, as well as articles which, because of their size, mass or configuration may be carried unpackaged or carried in cradles, crates or handling devices. Except for the carriage of radioactive material, the term does not apply to goods which are carried in bulk, nor to substances carried in tanks.


Bulk goods will be shipped in a bulk container.

"Bulk container" means a containment system (including any liner or coating) intended for the carriage of solid substances which are in direct contact with the containment system. Packagings, intermediate bulk containers (IBCs), large packagings and tanks are not included.

A bulk container is:

  • of a permanent character and accordingly strong enough to be suitable for repeated use;
  • specially designed to facilitate the carriage of goods by one or more means of transport without intermediate reloading;
  • fitted with devices permitting its ready handling;
  • of a capacity of not less than 1.0 m³;

Examples of bulk containers are containers, offshore bulk containers, skips, bulk bins, swap bodies, trough-shaped containers, roller containers, load compartments of vehicles.

Bulk containers can be closed, sheeted open top, or flexible.


"Tank" means a shell, including its service and structural equipment. When used alone, the term tank means a tank-container, portable tank, demountable tank, or fixed tank as defined in ADR, including tanks forming elements of battery-vehicles or MEGCs (see also "Demountable tank", "Fixed tank", "Portable tank" and "Multiple-element gas container");

NOTE: For portable tanks, see in ADR

"Tank-container" means an article of transport equipment meeting the definition of a container, and comprising a shell and items of equipment, including the equipment to facilitate movement of the tank- container without significant change of attitude, used for the carriage of gases, liquid, powdery or granular substances and, when used for the carriage of gases as defined in, having a capacity of more than 0.45 m³ (450 litres);

NOTE: IBCs which meet the requirements of Chapter 6.5 are not considered to be tank-containers.

Larger Loads

The term “larger loads” is not defined in ADR, but is used here in the main table listing dangerous goods, allowable quantities and restrictions.

It is included in this document as a means of providing guidance to officers on the escort requirements for vehicles carrying loads with weights above:

  • a maximum allowable comprising entirely of limited quantity goods; or,
  • for vehicles carrying above what would be an exempted quantity of a particular entry/commodity.

Mersey Tunnels Code List Rules & Exemptions

Table Notes

If multiple UN numbers are transported the most restrictive provision applies to the whole load.

Limited Quantity

The package size is determined by the UN number and will be labelled with the LQ label.

Where a limited quantity is specified for a particular entry, loads of up to and including 8T of limited quantities are exempt from tunnel coding and may pass through.

Loads of limited quantities greater than 8T are restricted according to the UN number or numbers carried.  The most restrictive being applied.

Exempted Quantities

Prohibited goods may be exempted from restrictions in accordance with the Transport Category column 1, the exempted quantity being given in column 2


Column 1

Transport Category

Column 1A

Classification codes for

1A & 2A


Column 2

Load Limit Litres or Kg


No Exemption




1.1B to 1.1J, 1.2B to 1.2J 1.3C 1.3G 1.3H 1.3J 1.5D





1.4B to 1.4G and 1.6N





Unlimited amount


Package sizes and maximum number of packages allowed in a vehicle

The maximum allowable package size varies according to the hazards of the material being shipped and the packaging material itself, meaning a single value cannot be listed in this guidance.

Full details can be found in ADR.

Escort Requirements

Escort requirements are determined in accordance with tunnel codes and the hazards presented that particular entry.

  • No escorts are required for any goods showing "Passage allowed"
  • Escorts are required for bulk loads and large loads of packaged goods with B/E, C/E tunnel code.
  • Escorts are required for large loads of packaged goods with D/E tunnel code

In addition to the above escort requirements, the Mersey Tunnels Byelaws have been applied and may allow passage of what would otherwise be a prohibited load through the Kingsway tunnel.

Specific details of these entries and associated restrictions are given in Annex A of this document, included after the main dangerous goods listings.

In deriving these exceptions, the authority considered several factors such as the characteristics of the tunnels, additional operating measures, the availability of alternative routes, scheduled traffic management and tunnel closures to derive a list of commodities which are permitted passage under escort in the Kingsway Mersey Tunnel during prescribed hours. This list is included as Annex A to this document.

Mixed Loads              

Mixed loads may be permitted in accordance with the following calculation

Transport Category




Quantity x 50



Quantity x 20



Quantity x 3



Quantity x 2



Quantity x 1



      Total no greater than        1000



The load comprises:

1 x 10kg package of transport category 1

      (1*10)*50     =500

2 x 20kg packages of transport category 2

                                                       (2*20)*3      = 120

2 x 20kg packages of transport category 3

                                                       (2*20)*1      =40



For articles, total mass in kilograms of the articles without their packaging’s

(for articles of Class 1, net mass in kilograms of the explosive substance;  For dangerous goods in machinery and equipment the total quantity of dangerous goods contained therein in kilograms or litres as appropriate)

For solids, liquified gasses, refrigerated gasses and dissolved gasses, net mass in kilograms.

For liquids, the total quantity of dangerous goods contained in litres.

For compressed gasses, absorbed gasses and chemicals under pressure, the water capacity of the receptacle in litres.

Dangerous Goods Restrictions/Listings(PDF, 3.62MB)

Any vehicle that is conveying a substance covered by the ADR Regulations must stop at the designated Police Declaration points prior to entering the Mersey Tunnels and the driver is to declare to Mersey Tunnels Police the nature and quantity of that substance

For the avoidance of doubt failure to declare is a contravention of the Mersey Tunnels Byelaws (PDF)and the driver may be reported and summonsed for contravening Section 7 of the Mersey Tunnels Byelaws (Dangerous Goods, Vehicles or Containers). 

If you have any queries please contact Mersey Tunnels Police Combined Control Centre on 0300 3000 999 (recorded line) for clarification