On Thursday and Friday GMB union members working for the UDAW Union went on a half day strike. GMB workers, who represent the lowest paid workers within USDAW, are in dispute over pay and USDAW’s refusal to engage with GMB over the implementation of a hybrid working policy (a fact that is made all the more ridiculous when one considers USDAW’s response to the strike – on which more below).

The local branch is on Twitter under the handle @gmbx39 and are updating followers on developments there, please give them a follow if you can and send a message of solidarity and support.

GMB’s plan was to strike on the morning of 27 and 28 October 2022 but, in response, USDAW upped the ante of the dispute and, in doing so appear to have adopted tactics that should be a concern to all trade unionists, and especially all USDAW members – I will say a bit more on this below. I am pleased to say the strike went ahead despite USDAW’s threats.

After being served with notice of the industrial action USDAW issued GMB members the following letter:

In this post I want to explore two aspects of this letter, the idea of part performance and the idea of the lock out.

Part Performance

What GMB were planning in the industrial action was for members not to work their contractual hours of work between 7am and midday on the two days of action but to resume their duties for the rest of the day. In doing this the workers would be breaking their employment contract in that they were only planning to perform a part of their contractual obligation.

Historically employment law has developed a principle that a worker must fully perform their contractual obligations for the contract to be binding. The history is an interesting one founded on the experience of ship owners contracting sailors sail only for them to jump ship at some exotic location halfway through the job and then sue for half of the fee since they had done half the job (I paraphrase somewhat but there were a number of cases like this in the eighteenth century, the most famous being Cutter v Powell in 1795 although that case was much harsher, the sailor died during the job and his widow unsuccessfully tried to obtain a percentage of the wages earned).

The contractual principle of partial performance dictates that when a worker only gives partial performance then the employer has a choice, either accept the performance (in which case the worker will be paid for the portion they worked) or reject partial performance. In a work context this principle has been supported at the highest level (House of Lords) in Miles v Wakefield Metropolitan District Council [1987]. However, the Court of Appeal’s case of Wiluszynski v London Borough of Tower Hamlets (1989) is probably the best example of how the principle works in an industrial action context.

The claimant was a member of the trade union NALGO (now part of Unison) and was engaged in industrial action which amounted to action short of a strike. The claimant worked for a local authority. For the duration of the industrial action NALGO members refused to answer specific enquiries from councillors, which amounted to about three hours of work over the month the industrial action was ongoing. The union members were told every day that the employer would not accept partial performance and the Court of Appeal found that, despite the claimant completing 98% of their duties (assuming a 35-hour week) the employer was justified in refusing to pay the claimant any salary over the whole month.

Partial performance can, therefore, be a very harsh contractual doctrine but it is still the case that what USDAW have done – while a stain on its character as a trade union – is lawful. Strangely, employers are keen to use it against unions but not to combat the ‘quiet quitting’ phenomena. That said, although currently lawful there is the possibility that if Unison is successful in its challenge against the Court of Appeal’s decision in Mercer on whether a claim of trade union detriment for participating in industrial action is permissible that position may change (so far as I can see the Supreme Court have not yet decided whether to hear the case).


Although it is referenced (section 238) the Trade Union and Labour Relations (Consolidated) Act 1992 – the main source for statutory industrial action law – does not provide a definition of a lock-out. The Employment Rights Act 1996, at section 235(4), when it states a lock-out is “the closing of a place of employment or suspension of work or a refusal by the employer to continue to employ any number of persons done with a view to compelling persons employed by the employer to accept terms or conditions of employment or affecting employment does.” However, that definition applies only to claims under the Employment Rights Act and broader definition is possible elsewhere – Express and Star Ltd v Bundy (1988).

The lock out is a tactic of employers that prevents a worker from fulfilling their employment, for example by closing an establishment or padlocking doors – it is not illegal and is not even necessarily a breach of contract (whereas its counterpart – the strike – always is!). Throughout history the lock-out has been a tool used by employers to diminish the power of unions in the workplace, a famous instance being the Derby Lock-Out introduced in this short video:

A lock out is not normally illegal (even the International Labour Organisation legitimises its use) but it is almost invariably used as a means to attach and delegitimise the exercise of union organisation in a workplace. It is not used that often because many employers recognise it inflames and lengthens disputes rather than resolving them.

USDAW in its letter to GMB members stated that if members took part in the strike, they would not accept partial performance but then, also locked them out so that they could not even give partial performance had they wanted to (while requiring all other staff to work from home – the availability of which is one of the issues of dispute!). The result is that USDAW, the trade union, has fallen in step with the worst of the rogue employers and utilised longstanding union and strike busting methods.

I sincerely hope the union movement unites behind this small GMB branch and calls out USDAW for its dereliction of trade union’s ideals. It may be a motion of censure is also appropriate at the next TUC Conference?

And, more pertinently, I hope USDAW’s actions become known among its membership at large. To those I would say – union executives are elected to office with your blessing. In cases like this, it is incumbent that those General Secretaries, AGS’, and executive members who have supported this approach are removed from office at the next opportunity before their actions taint the rest of the trade union movement.


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