Last night, Camden residents and councillors had a chance to hear from our new police Borough Commander, who has the task of overseeing the six-month trial merger of Camden and Islington police.

Chief Superintendent Roper has an impressive grasp of her brief, both in breadth and depth, and she appears to be impeccably suited to the job.

But whether the job remains suited to Camden is another matter. Camden and Islington police are being merged on a ‘pathfinder’ basis, with an explicit guarantee that if the trial does not succeed, the boroughs will have their separate borough commands restored.

Indeed, Camden’s Cabinet member for Community Safety went further and said that if Camden Council itself was not satisfied, the merger would be undone.

But it’s unclear what the definition of success is, with the Borough Commander confirming to me on Thursday that the definition has not been set. Does it mean lower crime overall? Or lower incidents of specific serious crimes? Or higher rates of arrests or convictions for crimes?

Or does it mean that the rate of crime reduction accelerates? After all, crime has fallen in Camden by a fifth since 2010, so a small reduction would be a disappointment.

Indeed, Sadiq Khan’s draft Police & Crime Plan for London, published last month, abolished targets for crime reduction across London. This will make it harder to assess the Met’s success on a city-wide basis.

But at a Camden level, we should know what success looks like and it should have been decided before the trial began. The merger was announced in November, and two months on, we still don’t have answers.

With the trial’s success – and thus its permanence – being assessed when it wraps up in July, we’re already running out of time to work out how it will be judged.

The Met and Camden Council must be clear, as soon as possible, about how they will assess the success of this scheme, and set objective metrics by which that success can be assessed. If they aren’t, the goalposts will inevitably move to suit whoever sets them, and not to suit the people of Camden.