An undertaking to use “reasonable endeavours” requires the solicitor giving the undertaking to those take steps as reasonably necessary as a prudent person would consider reasonably necessary to achieve the objective, while still having regard to their own commercial interests. In broad terms, this is a balanced approach enabling the individual giving the undertaking to carry out the obligation without exhausting all possible options and completely sacrificing their commercial interests. In practice, “reasonable endeavours” allows the solicitor giving the undertaking to exercise judgment. If there are multiple courses of action, the person giving the undertaking is not usually required to pursue all of them, nor to pursue indefinitely if the prospects of success appear unlikely. If the solicitor giving the undertaking can demonstrate that their efforts met an objective standard of reasonableness, failure to achieve the objective may not amount to a breach of the undertaking.  

While “reasonable endeavours” are perhaps less stringent than “best endeavours”, regulators and courts have consistently emphasised that undertakings should not be given unless the solicitor can ensure compliance. However, the scope of what is considered “reasonable” remains context-dependent and can lead to uncertainty when assessing compliance. 

An undertaking using “best endeavours” is the next best thing to an absolute obligation. This is significantly more onerous as whilst it does not require the person giving the undertaking to pursue compliance at all costs, it requires them to take all reasonable steps to pursue the objective with determination and persistence, whether or not that would potentially create an inconvenience or incur costs. As mentioned, “best endeavours” is often treated as approaching an absolute obligation, particularly where a solicitor has control over the relevant steps, a failure to comply with the undertaking may therefore prompt close scrutiny of what the solicitor did – or did not do. Using “best endeavours” to achieve an undertaking can be particularly dangerous for a solicitor giving it as they may be susceptible to criticism or even disciplinary action if the outcome is not achieved and it is alleged that more could have been done to achieve the outcome.  

In residential conveyancing, it is common for undertakings to relate to post-completion matters such as mortgage redemption and registration. Giving an undertaking with “best endeavours” is particularly risky where performance of the undertaking is dependent on other parties, such as a lender, managing agent or HM Land Registry. Even where a delay is caused by a third-party, the solicitor will be expected to ensure that every possible step was taken to overcome the issue. Undertakings for “best endeavours” are therefore inherently riskier. They invite retrospective analysis of conduct against a high and somewhat elastic standard. “Reasonable endeavours” while still demanding, provides a clearer benchmark against which compliance can be assessed. 

While neither imposes an absolute obligation on solicitors, it is important to consider that both types represent fundamentally different standards of obligation. “Reasonable endeavours” permits judgement and proportionality. “Best endeavours” demands persistence, exhaustiveness and a willingness to subordinate competing considerations.  

This blog was written by Mark Scott & Marice Ximines