Our UK-based company (approx 40 employees) was acquired by a larger company - at the end of 2011.

The acquiring company (European) reassured us that they had performed previous acquisitions and integrations, and had 'teams' dedicated to those purposes.

That turned out to be complete nonsense - they simply did not. The acquiring company also made 2 other acquisitions at the same time, one of similar size to ourselves - and they seem to be experiencing the same thing.

The entire year of 2012 seemed to be spent figuring out ourselves where we fit into the larger picture. Leadership by senior management in the acquiring company has been poor, and communication even worse.

We are now into March 2013, and in the past 3 months - have seen the departure of two members of staff that were senior managers in the acquired company. This seems to have pushed morale levels in our UK office to an all-time low.

Staff no longer seem to have a contact point for raising problems with integration, and what was previously a happy working environment is deteriorating.

The local HR manager is one of those that are also completely disillusioned by the acquisition and integration process so far.

There is also 'supposed' to be a degree of separation between myself (corporate) and the others in our office (development/support) - but the levels of frustration are almost palpable.

The risk is that - if left unchallenged - this could result in the departure of further key staff.

How do you even begin to raise this towards senior management?

Take a simple survey of all 40 employees, using pre-set questions.
Summarize the findings into the most succinct list you can. Make sure it doesn't take more than 3 minutes to say out loud.
Go pound on the takeover company's desks, spelling out the dangers of losing everybody.

Maybe that is what they want. Some takeovers are intended to either lose all staff or to lose money to show a loss for some reason. I would ask them that at the end.