Why So Many New UK Managers Fail in Their First 90 Days

By Business Coach Peter Boolkah

The first 90 days in a management role are often treated as a proving ground. New managers arrive keen to show they were the right choice, full of energy and intent, and determined to make an immediate impact. Yet it is precisely this mindset that causes so many of them to stumble. In the UK in particular, we have created a system that promotes people into leadership roles without properly preparing them for what the job actually requires, and then acts surprised when they struggle.

Research consistently shows that a significant proportion of UK managers receive no formal management training at all. The Chartered Management Institute has highlighted for years that more than four in five managers have never been trained, and that this lack of capability feeds directly into low engagement, higher staff turnover and weaker performance. Against that backdrop, it is hardly shocking that many new managers fail within their first two years. What is more revealing is how quickly things start to go wrong. In my experience, the seeds of failure are often sown in the first three months.

I recently ran a poll on LinkedIn asking people what they found hardest when stepping into management. The response was striking. Nearly half said the biggest challenge was learning to coach rather than micromanage. A further third said the real struggle was building systems that stop them from being dragged back into day-to-day work. The comments made one thing clear: people know the job changes the moment they are promoted, but most are not equipped for that shift because they lack the skills, support and permission to lead differently.

Too many new managers spend their first 90 days trying to prove they deserve the role. They jump in to fix problems their team should be handling. They close deals themselves instead of developing their salespeople. They answer every question instead of teaching people how to think. It feels productive in the moment and is often rewarded in the short term, but it is a trap. Within a few months, they are exhausted, their team has become dependent, and senior leaders are wondering why nothing seems to have improved.

This behaviour is understandable. Most managers are promoted because they were good at their previous job. When pressure hits, they revert to what they know. The issue is that management is not an extension of individual performance; it is a fundamentally different role. The measure of success is no longer how much you personally deliver, but how capable your team becomes without you. Without training or guidance, many people never make that mental shift.

The first three months should not be about heroics. They should be about setting expectations, building simple systems and creating clarity around decision-making. New managers need to spend time understanding where their team adds value, where it gets stuck and where responsibility truly sits. They need to coach people to solve problems themselves, even when it would be quicker to step in. That can feel uncomfortable, particularly for high performers, but it is the only way to build a resilient team.

There is also a broader cultural issue at play in UK organisations. We still tend to reward busyness and firefighting, rather than calm leadership and capability building. New managers take their cues from what they see above them. If senior leaders value control over trust and speed over development, then inexperienced managers will follow suit.

If we want fewer managers to fail in their first 90 days, we need to stop setting them up to fail. That means investing in proper management development before and during promotion, and being clear about what the role is and is not. You were not promoted to do more work. You were promoted to raise the capability of the people around you. When new managers understand that from day one, those first 90 days become a foundation for long-term success rather than the beginning of a slow decline.