What is an Undertaking?

Undertakings are a common part of the Court process, and are defined as a legal promise to do, or not do, something.  An undertaking is a promise to the Court, and if you break it there are ways that it can be enforced.  If broken, you could be at risk of being fined, or put in prison for a short period of time, but these are the most extreme consequences.

Undertakings are commonly given in family law cases, either in financial matters or in respect of children.

If undertakings are given in children matters, it is normally to prevent one parent from doing something or to ensure another parent does do something. Restrictive undertakings may be things such as one parent promising not to leave the country for a specific period or agreeing to certain requirements relevant to their case.

In financial matters, an undertaking can be given where it is not always possible for one party to complete a financial action straight away. For example, if one party is given the former matrimonial home but still requires their ex-partner to stay on the mortgage, it is not unusual for the receiving party to undertake to try and obtain a mortgage and release the other party.  This can also be applied to releasing one party from the liability of loans.  In most situations, it is best to clarify that the party making the promise will do so to their “best endeavours”.  This avoids the possibility of placing the promising party in an impossible position whereby they cannot release the other party despite their best efforts.

A case was heard recently which shows the dangers of entering into an undertaking without comprehending the full implication of doing so. In Birch v Birch, the parties entered into a consent order which detailed how the couple had decided to divide all of their joint assets. This order is sealed by the court, and it is very rare that these can be varied. The court encourages that they be seen as “final” and not something people can keep coming back to, to change.

Within this consent order, Mrs Birch made an undertaking to try and release her ex-husband from their joint mortgage. This is very common in consent orders, as it provides sufficient flexibility for the receiving party, as well as reassurance for the other. However, in this case, Mrs Birch was given until 30 September 2012 to release her ex-husband, and if she failed then the property was to be sold.  This would be two years on from the consent order.

On 18 November 2011, Mrs Birch made an application to vary the consent order to extend the time she had to release Mr Birch from the mortgage to until their youngest child turned 18 or until either of their children completed full time education (commonly 18).  This was an attempt by Mrs Birch to change her undertaking.

Unfortunately for Mrs Birch, they denied her application.  It was argued that her undertaking was part of the true nature of the consent order, and to change it would be to change the whole order which could not be justified.

What this case shows is that you must be very sure when you agree to make an undertaking in Court, as it is very difficult to alter them in the future.  It is also important that you consider how they will affect you in the near future, and to be aware of your circumstances going forward.


Undertaking in family law - rhw family solicitors in Guildford, Surrey. If you’re asking “what is an undertaking”, thinking “should I enter an undertaking?” or you have any further queries about this subject, then please contact rhw family law Solicitors in Guildford on , complete the form on our contact page or you can email us:

This article about undertakings in family law was first published on the 7th of August 2015 and last updated on the 8th August 2021.