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What the data shows and what has changed

London is entering one of the most time-sensitive office cycles in decades. While occupiers and developers are extending planning horizons, the windows in which they can act appear to be narrowing. This tension between longer-term strategic thinking and the practical constraints of transactional timing is reshaping London’s competitive landscape.

The development pipeline provides one of the clearest illustrations of this shift. Although a significant volume of future space is nominally in the system, a comparatively small proportion of that pipeline is actually committed, according to our analysis. As a result, visibility of space delivering in 2026 and beyond remains limited, and the early years of this period look thin, with just 10m sq ft of speculative space currently under construction between 2026 and 2029, equating to just 1.7 years’ worth of average new or refurbished take-up.

Partly because of this supply-side shortage, the timing profile of occupier demand has fundamentally altered. Many requirements are surfacing earlier than before yet deal progression has lengthened. Pre-lets provide a useful case study. Typically, we report the lead-in time from an occupier committing to a pre-let and the practical completion date. Since 2020, the average lead-in time for London pre-lets is 12.1 months prior to practical completion. In figure 2, the variation by size band is clear. Larger pre-lets are being signed further ahead of practical completion over the last few years, whilst smaller pre-lets are evolving in the opposite direction – signing much closer to the anticipated occupation date than even three years ago.

Increasingly, larger occupiers are beginning their search process earlier, which is not always captured in traditional market analysis. By extending the typical pre-let lead-in data to include when the requirement first launched, it shows a more accurate picture of the occupier journey. On average, searches for pre-lets of 50,000 sq ft or more, signed since January 2020, start 38.4 months ahead of the target occupation date, almost double the conventional pre-let lead-in time for equivalent-sized deals of 19.1 months prior to practical completion.

Figure 3 (above) shows how the divergence increases with scale, with searches for 200,000 sq ft or more starting 50.6 months ahead of the target occupation date.

Overlaying this with lease event data adds further complexity to market timing. Over five thousand leases are due to expire between 2026 and 2030, representing nearly 55m sq ft of potential future demand. The expiry concentration varies by submarket and suggests timing pressure may be acute in parts of London. For example, the City Core will see 17.9m sq ft of leases expire by the end of 2030, accounting for a third of all lease expiries across London.

These structural changes are occurring against a backdrop of shorter commitments, with the overall average term certain across London falling below five years for the first time, as can be seen in figure 4, which includes all transaction types.

This has compressed the intervals between key decision points. Occupiers must navigate more frequent decision cycles, with greater exposure to construction timelines, competition and external shocks. There is nuance to this trend. Post-pandemic, the shortening of term certains became more acute for all transaction sizes.

In 2025, for deals of 60,000 sq ft or more, the average term certain increased to 14.1 years, sitting above the 10-year average of 13.1 years. Again, this shows a divergence in market activity based on scale.

Traditional measures of market activity have also become harder to interpret. Rising numbers of early-stage requirements have potentially inflated statistics on active demand and space under offer. At the time of writing, there is nearly 3.7m sq ft under offer across London, and 11.8m sq ft of named active demand. Given the analysis above shows continued divergence for larger requirements, it is no surprise 12 of the current active searches are for 200,000 sq ft or more, many of which are targeting space well ahead of delivery.

Implications and challenges

The combined effect of these shifts is that market participants are increasingly operating on misaligned timelines.

Occupiers sometimes underestimate how quickly preferred opportunities can be captured by competitors, particularly in core locations with limited options. As a result, many occupiers find their strategic window narrows more quickly than expected, reducing their leverage and increasing their exposure to construction and delivery risk.

For developers, certainty of delivery timing has become a central differentiator in the market. When funding partners are more cautious and pre-lets constitute a growing share of activity, developers must provide clearer programme timelines and must commit to design and specification choices earlier. Already strained financing structures are becoming more sensitive to these timing uncertainties, which then affects viability.

The result is a systemic timing asymmetry.

The reality: When theory meets practice

The data suggests occupiers should engage earlier and developers should think longer term to capture this demand. In reality, both sides face constraints that make this difficult.

The result is a mismatch between the theoretical benefits of long-term alignment and the practical constraints that shape real-world behaviour.

• Early engagement often begins when a scheme is least certain for developers yet occupiers entering the market early expect clarity on delivery dates, specification and sustainability outcomes.
• For developers, accommodating occupiers’ bespoke requests can trigger delays or additional regulatory steps, precisely when funders are looking for momentum.
• Occupiers struggle to act as early as they should. Requirements often change, making developers cautious about relying on early interest.

The playbook for market players

Success will be defined by the ability to anticipate timing pressure and respond proactively.

Occupiers will need to begin strategic planning earlier. Early scenario modelling, particularly around construction duration and fit out timelines, will become essential. Engaging with developers at earlier stages of scheme evolution will help secure competitive pipelines and provide greater clarity around what is realistically deliverable. Organisations will also need to revisit internal governance processes to reduce bottlenecks and ensure decision making can keep pace with the market. For those weighing stay versus go scenarios, timing must be a core variable given the shorter lease structures now common across London.

Developers will need to adapt behaviours to meet the timing demands of occupiers. Clearer communication around construction programming, contingency planning and design finalisation will be essential to reinforce confidence in deliverability. Engaging occupiers earlier, before full design certainty exists, will become more common as pre-lets increase in volume. There is also a greater need for developers to consider developing speculatively, given off-plan pre-lets account for just 6.1% of pre-lets signed across London since 2013. Developers may find greater flexibility in specifications and an ability to absorb late-stage adjustments will improve the likelihood of aligning schemes with occupier decision cycles.

The outlook in the short and long term

In the short term, transactional volumes may appear subdued because deals are taking longer to progress.

This elongation is likely to feature for the next few years, unless there is a significant shift in schemes given the green light for redevelopment (see our upcoming Paper 3 – Building at the Limits). Space that is already fitted or capable of rapid delivery may see elevated interest as it allows occupiers to respond more quickly than new developments permit. Occupiers that do not adapt their decision-making pace risk losing out on preferred options or encountering fewer viable alternatives. Without conscious correction, the gap between perceived and actual time available will continue to widen.

Looking further ahead, early strategic planning is expected to become standard practice for both occupiers and developers.

Pre-lets will play a larger role in shaping scheme phasing and financing models. The visibility and reliability of delivery timelines will become as important a differentiator as location or specification, contributing to a wider polarisation of the market. Developments that can demonstrate certainty and clarity around timing are likely to outperform, while schemes with ambiguous delivery profiles may struggle to attract early commitments. London’s overall competitiveness will increasingly hinge on the ability of market participants to align their timelines more effectively and to manage the extended journeys that now characterise both occupier and developer decision-making.