You cannot legislate, so the cliche goes, for common sense. Within the judicial process, of course, nobody actually calls it common sense. Instead, it tends to proceed under the banner of judicial discretion. However it is termed, the decision in Dadourian Group International Inc v Simms & Ors [2006] looks like an unhelpful attempt to codify it.

Let us take stock of the situation Dadourian addresses. In the late 1980s and early 1990s, a series of cases, culminating in Derby v Weldon (nos 3 and 4) [1990] and Babanaft International Co v Bassatne [1990], resulted in the English courts deciding that they could grant worldwide freezing orders – that is, ones that imposed conditions on a defendant's assets wherever they were.

Two reasons were frequently cited for the development. First, a worldwide injunction avoided the need for a 'multiplicity of proceedings'. The claimant did not need to start separate proceedings to freeze assets in every jurisdiction where he found them, if a single injunction in this country would do the job. Second, the worldwide freezing order was needed to combat the increasingly international nature of fraud.

The tension between these two reasons was never really highlighted. If someone is happy to commit fraud, the chances are they may also disobey a freezing order. True, the freezing order is worth having and the defendant might not ignore it completely. But the injunction in a fraud case is often obtained not so much in the hope that the defendant will obey it, but that third parties who hold the defendant's money will have qualms about ignoring court orders that the defendant will lack.

But such qualms are less likely to be held by third parties who are overseas. Third parties abroad are not usually in contempt if they assist a defendant to break a worldwide freezing injunction, and following Babanaft, the injunction itself must say so. Thus, while after Babanaft and Derby v Weldon the court required the claimant to undertake not to seek similar relief in other jurisdictions (to avoid a 'multiplicity of proceedings') in cases of fraud, at least, it frequently varied the undertaking to allow him to do so because there was no other way the claimant could be sure to tie down the assets.

I do not recall any practitioner complaining of the need for rules as to how the discretion should be exercised. The court allowed claimants to commence proceedings abroad when it was sensible and fair in the light of the evidence, and it stopped them doing so when it was not.

Enter the Dadourian Group, which had commenced proceedings against a variety of defendants and obtained a worldwide freezing order complete with its usual undertaking not to enforce the order abroad or obtain similar orders elsewhere without the court's permission.

The claimants had sought and obtained a variation of the undertaking that permitted them to enforce the order in Switzerland. This they then did. Ultimately, the Swiss proceedings did not give them any real value, but the costs of the exercise alone were worth fighting about and so the matter ended up in the Court of Appeal. The Court of Appeal, while dismissing the appeal, decided to codify the basis on which the discretion to vary should have been exercised.

With an eye to posterity, the code is named The Dadourian Guidelines – and guidelines they must be. One could hardly term them rules when an explanatory note to the first guideline emphasises that judges must have "maximum flexibility". What then follows contains few surprises. The variation should be "just and convenient" and "not oppressive". "All the relevant circumstances and options must be considered" (part of guideline 2). The interests of the various parties "should be balanced" (part of guideline 3). The standard of proof required to show assets are within the jurisdiction of the foreign court is that the claimant must show there is a "real prospect" (guideline 6) and so on.

Nevertheless, as with any attempt of codification, there will be argument about emphasis and interpretation. First, there is emphasis on protection of the position of third parties, particularly those who have no connection with the defendant.

It may now be a condition of the claimant being given permission to enforce abroad that he will have to extend his undertaking in England to pay the legal costs of third parties abroad who have to deal with the ancillary proceedings. One wonders whether the courts where the ancillary proceedings are being brought ought to have some say in the matter.

Second, the evidence in support of the application must contain "all the information (so far as it can reasonably be obtained in the time available) necessary to enable the judge to reach an informed decision, including evidence as to the applicable law and practice in the foreign court, evidence as to the nature of the proposed proceedings to be commenced and evidence as to the assets believed to be located in the jurisdiction of the foreign court and the names of the parties by whom such assets are held".

Some of this material may well be relevant to the decision that the court will make, but much may not be. Perhaps it would have been better for the claimant to set out the relevant facts (subject to his obligation of full and frank disclosure if the application was made without notice) and – if the defendant felt that some factor was material and had been omitted and misdescribed – to identify what it was.

Third, the claimant is less likely to obtain permission to commence enforcement proceedings abroad if, by doing so, he will obtain protection 'superior' to that afforded by the worldwide freezing injunction. There will be plenty of scope for argument here. It is easy to see that ancillary proceedings that give priority in insolvency may give rise to difficulties because third parties will be affected.

But in other cases, if the claimant is able to show a genuine risk that the English worldwide freezing injunction will not be observed, why should it be his problem that the freezing procedures of courts of another country are harsher than those of his own? Should not the laws and courts of the state in which enforcement is sought have more of a say in what is, or is not, appropriate relief in their own jurisdiction?

Finally, the application to vary the injunction should be made "on notice" but "in cases of urgency, where it is just to do so, the permission may be given without notice".

The claimant will often want to make the application without notice not because of urgency, but to achieve the element of surprise on a dishonest defendant who does not know that the claimant has discovered (and is in a position to freeze) his foreign assets.

It is unfortunate that the word "or" was not included after the word "urgency". No doubt someone will now argue that under the Dadourian Guidelines, urgency is now the only ground on which an application to vary the under-taking can be made without notice.

But the argument should fail – provided, of course, the court interprets the Dadourian Guidelines with a bit of common sense.

Robert Hunter is a partner at Allen & Overy.