Concurrent Delay in Construction Contracts – Clarity at last?

Blackburn bus station has provided the unlikely backdrop to the Technology and Construction Court’s (TCC’s) latest attempt to provide some much-needed clarity on the thorny issue of concurrent delay in construction contracts. Here, James Flynn looks at how a recent case of concurrent delay was dealt with in Court and brought light to an area of law where there remains several conflicting authorities.

HHJ Davies, sitting as a High Court Judge in Manchester, last week handed down judgment in the case of Thomas Barnes & Sons PLC (in administration) -v- Blackburn With Darwen Borough Council [2022] EWHC 2598 (TCC) (

The case involved the perennially difficult question of how to deal with a contractor’s claim for an extension of time when there are two separate delaying factors, one for which the contractor is responsible and one that would ordinarily entitle the contractor to an extension of time. Such a situation is known in the construction industry as concurrent delay.

Despite claims relating to concurrent delay being far from uncommon, the correct way to deal with such claims remains a matter of significant legal debate, and a disappointing lack of clarity. The decision in the Thomas Barnes case unfortunately does little to improve this position.

There are three broad schools of thought for dealing with a claim for concurrent delay, as set out below:

One. The Society of Construction Law Delay and Disruption Protocol favours what is know as “first-in-time” approach, namely that where one delay has already caused a delay to the completion date, a subsequent delaying event must then be disregarded, unless that further extends the completion beyond the original consequences of the first delay event.


Two. Others advocate a simple test of whether any particular delay event would have delayed completion in the absence of other delaying events for which the contractor may be responsible. If the answer to this is yes, then the contractor should receive an extension of time.


Three. Another view, supported by some case law authority, is that if any delay event entitling the contractor to an extension of time is of “equal causative potency” with another delay event which is the contractor’s risk, then an extension of time will be awarded. This approach will normally require some kind of critical path analysis to be undertaken.


Whilst some recent (non construction) cases have favoured the first-in-time approach, much time has been spent debating the correct way to deal with concurrent delay, with no consensus being reached and no clear guidance from the courts.

Which approach is to be adopted can significantly change a contractor’s entitlement to time, cost and relief from Liquidated Ascertained Damages (LADs). It is little wonder so much effort is being spent arguing for one approach, or another.

The TCC in Thomas Barnes adopted the view expressed in the current edition of Keating (a leading construction law text book) that the contractor would be entitled to an extension of time if an employer risk delay event was an “effective” cause of delay, even if there was another “concurrent cause of the same delay” for which the contractor was responsible. The Court went on to support the view that, in such circumstances, the contractor would not be entitled to loss and expense for any period of concurrency.

The case revolved around two competing causes of delay to the project, one relating to roof coverings, which was the contractor’s responsibility, and one relating to issues with the steel frame, which was the employer’s responsibility. Both events were found to be critical to completion and concurrent.

Although the steel frame delay occurred before and continued after the roof covering delay the Court took the view that both causes of delay were on the critical path and both were concurrent, and that the contractor was entitled to an extension of time for the period of the steelwork delay of 119 days.  However, the contractor was not entitled to any prolongation costs other than for the period of the steelwork delay that was not concurrent with the roof covering delay (a period of only 27 days).

Whilst this judgment appears to support the position that the first-in-time approach adopted by the Society of Construction Law (SCL) is not now correct, this is an area of law where there remains several conflicting authorities. Guidance from the Court of Appeal on the matter would therefore be welcome.

By James Flynn