Research and analysis

Executive Summary: Exploring storage capacity to meet customs demands 2018

Published 15 July 2025

This report was commissioned under the Conservative administration (2010 to 2024), and conducted in 2018.

HM Revenue and Customs (HMRC) Research Report 822.

1. Introduction and methodology

This report covers research on behalf of HM Revenue and Customs (HMRC). It measures the current storage capacity across different types of storage sites and other premises that are government-authorised to carry out specific customs procedures and checks, as well as unauthorised storage sites. It also looks at their ability and willingness to expand this capacity to meet potential increases in demand in the future.

The research covers 6 different groups:

• four types of customs-authorised premises, including authorised consignors and consignees (CCs), customs warehouses (CWs), Designated Export Places (DEPs), and temporary storage facilities (TSFs)
• unauthorised general warehouses (UGWs), which might apply in the future for customs authorisations
• members of the UK Warehousing Association (UKWA), a trade association representing the largest warehousing operators, including third-party transport and logistics companies

This was a mixed-method research project involving:

• a random probability telephone survey of 536 storage sites, carried out from 18 October to 16 November 2018
• in-depth telephone interviews with 47 storage operators from 3 October to 16 November 2018

2. Storage type profiles

2.1 Authorised consignors and consignees (CCs)

CCs had a median capacity of 50,000 square feet. On average, they were using 85% of their space at any one time in the last 12 months, pushed up to 91% at peak times. This suggests that they had a somewhat higher utilisation rate than the average UGW (typically 81% utilised). From this, we estimate that:

• the overall storage capacity across the population of CCs was circa 196 million square feet
• the free (unutilised) capacity across all CCs was circa 10.7 million square feet
• they usually had a mix of parking bays (80% had these, with a median of 20 bays on site) and sheltered storage space (76%)
• around 3 in 10 (30%) offered refrigeration or other climate controls and they were more likely than the average UGW to deal with goods that would require specialist storage or containment, such as shipping or aircraft containers (76% of CCs), dangerous goods (63%), and sterile goods (36%)

2.2 Customs warehouses (CWs)

Sites incorporating a CW were typically slightly smaller than other types of storage sites, with a median square footage of 32,600. These sites also tended to be utilised to near-maximum capacity over past 12 months (typically 87% utilised, rising to an average of 90% at peak times).

A warehouse keeper can have part of their premises authorised as a CW, with the remaining part being either unauthorised, or authorised for a different purpose. Where operators had a CW, this usually took up over half of their total site (59% of the total space, on average), but in several very large sites, it was only a small part of the overall space. We estimate that:

• the overall storage capacity across sites with a CW was circa 587 million square feet and, within this, there was circa 180 million square feet in total CW-authorised capacity
• the free capacity across sites with a CW was circa 196 million square feet, including specifically circa 28.8 million square feet of free CW-authorised space
• like CCs, sites with a CW also had a mix of parking bays (73% had these, with a median of 20 bays on site) and sheltered storage space (79%)
• again, around 3 in 10 offered refrigeration or other climate controls (29%)
• sites with a CW were also more likely than the typical UGW to store dangerous goods (34%, versus 19% of UGWs)
• there is no limit on the amount of time goods can be stored in a CW, we found that the median amount of time that goods stayed in this type of storage was 45 days, just over 6 weeks
• nevertheless, the amount of time goods were stored in a CW varied widely, and in almost a third of these sites the goods were stored for more than 90 days

2.3 Designated Export Places (DEPs)

DEPs were not included in the quantitative survey. We carried out in-depth interviews with 11 DEP operators, who were able to give quantitative data on 12 DEPs (one was a multisite operator). Given the very low sample size, these findings are only intended to provide a very top-level picture.

Like other types of storage site, sites with DEPs varied considerably in size, but several of those we spoke to were larger than the typical CC, CW and TSF. As with other authorisations, site operators can apply for part of their premises to be a DEP — it does not need to take up the whole site. However, we found that whole-site authorisation appeared to be common. In 6 out of our 12 cases, the DEP space took up the entire premises.

The sites we spoke to tended to be highly utilised, often rising to 100 per cent utilisation at peak times in the last 12 months. DEP operators were aiming for very short turnaround times for goods passing through their space, with the ones we spoke to typically achieving 1-to-3-hour turnaround times.

2.4 Temporary storage facilities (TSFs)

Sites containing TSFs were typically around 40,000 square feet (the median value), so not as large as the typical CC, but slightly larger than most CWs. Across the year, these sites had typically been 82% utilised, rising to 88% at peak times. However, the TSF-authorised space usually made up a minority of the whole site (36% on average) — in some cases this space was simply a small cage (a ullage cage) capable of holding seized goods. The TSF-authorised space was also typically less fully utilised (71% utilisation at normal times across the year, and 79% at peak times). We estimate that:

• overall storage capacity across sites with a TSF was circa 208 million square feet, with the specific TSF-authorised capacity being circa 40.0 million square feet
• free capacity across sites with a TSF was circa 88.3 million square feet, and free capacity for the specific TSF-authorised sections was circa 3.69 million square feet
• sites with a TSF again had a mix of parking bays (77% had these, with a median of 20 bays on site) and sheltered storage space (79%)
• sites with a TSF were slightly less likely than CCs and CWs to offer refrigeration or other climate controls (19%, versus 30% of CCs and 29% of CWs), however, they were still more likely than UGWs to have stored sterile goods requiring refrigeration (29%), as well as shipping or aircraft containers (74%) and dangerous goods (51%)
• TSF operators are also authorised to store goods seized by HMRC, a third (32%) of these operators had not allocated any space for this, and, among the ones that had, the proportion of the TSF-authorised space set aside for seized goods tended to be very small — 11% on average
• goods can be stored in a TSF up to 90 days, we found that the median time for temporary storage was 4 days

2.5 UKWA members and other unauthorised general warehouses (UGWs)

We included smaller UKWA members (with under 500,000 square feet of storage) in the quantitative survey. Across these operators, we found the median storage capacity to be 45,000 square feet. The typical utilisation of these sites over the past year was 90 per cent (versus 92% at peak times), suggesting a general lack of spare capacity at any time of year.

We did not include large UKWA members (the multinational operators with at least 500,000 square feet of storage) in the survey, but did collect indicative quantitative data on utilisation from them across 14 in-depth interviews. This gives a sense that the sites run by these largest commercial warehousing and third-party logistics firms were typically close to fully utilised across the year. None said that they operated any sites where utilisation was under 50%.

In order to capture the smaller end of the storage market, with operators who would be less likely to join a trade association, we also included a random sample of UGWs in the quantitative survey. Across these, the median storage capacity was 41,800 square feet. Their typical utilisation rate in the past 12 months was 81%, rising to 87% at peak times, reflecting the seasonality of business for many general storage sites.

3. Summary statistics by type of storage site

3.1 Statistics for whole site

Site	Median capacity (square feet)	Typical utilisation	Peak utilisation
CCs	50,000	85%	91%
CWs	32,600	87%	90%
TSFs	40,200	82%	88%
UGWs	41,800	81%	87%
Small UKWA members	45,000	90%	92%

3.2 Statistics for authorised space within site

Site	Median capacity (square feet)	Typical utilisation	Peak utilisation
CCs	50,000	85%	91%
CWs	15,000	78%	85%
TSFs	5,000	71%	79%
UGWs	not applicable	not applicable	not applicable
Small UKWA members	not applicable	not applicable	not applicable

4. Ability and willingness to expand capacity

4.1 Plans to expand capacity

In the quantitative survey, within each type of storage site, more than half said they were unlikely (not very or not at all likely) to expand their overall capacity within the next 2 to 3 years. Very few — under one in ten for each type of site — had immediate plans to expand within the next 6 months.

4.2 Timelines for expansion

We found in the qualitative strand that physical expansion was often a last resort. Operators would first look at alternatives, such as reconfiguring their existing sites to match current demand, taking on more staff at existing sites, or extending the hours of operation.

Alongside other factors, this process increased the timelines around expansion. The overall timeline depended on the type of storage (storage requiring climate controls or other special needs would take longer), relocation distance, the time to scout new sites, the time needed to recruit and train new staff, and the time needed to apply for any relevant customs authorisations. We heard from operators that this process could range from 6 months to 3 years.

4.3 Barriers and challenges around expansion

The common barriers to expansion emerging from the qualitative interviews were around customer demand, risk aversion, speed of decision-making, awareness, geographic restrictions, cost, lease flexibility and skills shortages.

1. Customer demand was the predominant driver of expansion. Large operators tended to be reactive to customer demand, rather than opportunistic. Many noted that their customers were uncertain of their own situations due to the UK exiting the EU, which prevented them from making their own decisions around expansion.

2. Smaller, single-site operators that did not have a single, dominant customer group, often had a mindset more suited to expansion. We also heard about new digital businesses that were disrupting the warehousing and storage industry, by linking together these small sites with customers.

3. Smaller operators with flat management structures (with a handful of directors involved in expansion decisions) were able to make the call to expand much more quickly than some of the larger third-party logistics companies.

4. We commonly found a lack of awareness and understanding of the different types of customs authorisations (CCs, CWs, DEPs and TSFs), outside of the authorisations that operators already had.

5. Operators situated within busy ports or airports often faced a lack of space to build. Moving to new locations further away from ports of entry was considered risky in these cases, as it could force operators into changing established business models.

6. When considering the business case for expansion, operators took several cost variables into account, including the cost of relocating, buying land, installing new IT systems, and business rates. Access to finance, often from global investors, also became an issue for larger expansion plans at major ports.

7. Operators often rented premises from landlords. These landlords typically demanded fixed-length leases of 5 years or more, and would also commonly lease their whole site, rather than part of the site. Where these conditions did not match customer demand, this reintroduced a high level of risk into operators’ expansion decisions.

8. Many operators felt it was difficult to recruit staff with customs knowledge and experience, and that these staff were now more in demand across the industry due to EU Exit. They also noted what they saw as an ongoing lack of good quality skilled warehouse staff in areas such as picking and packing, forklift truck driving and IT.

4.4 Supporting expansion

Operators felt that HMRC could support efforts to expand capacity in the following ways:

• providing more information and guidance to operators about the different customs authorisations
• making applications for customs authorisations quicker and less bureaucratic
• potential financial assistance in the form of reduced business rates or grants
• more support to tackle skills shortages, for example through new apprenticeships or government-led training
• increasing the available space for new warehousing, for example by easing planning permission requirements or encouraging landlords to offer shorter leases