Every so often an idea emerges so obvious that you wonder why it took so long to be aired. The most recent was the opening to public access last week of a register of commercial leases in the State.

An accurate up-to-date register of the price being paid by businesses for commercial premises is clearly a useful piece of information for people in the market for such units.

Unfortunately, the register is unlikely to deliver fully on its promise – for now at least. It appears designed by a public servant with a view to how the sector should operate rather than by someone with an accurate knowledge of how it does work.

Thus, it has spaces for details of rent reviews, or rent-free periods of occupation, but no mention of “step-up clauses”, a feature of many leases signed these days.

Put simply, a step-up clause means the initial rent payable by the client will step up to a higher rent at some point, or points, during the lifetime of the lease.

The commercial lease return, as currently constructed, does not allow for this information. As a result, the figure contained in the register is likely to underestimate the rent being paid – at least after the first few years of the lease.

A second weakness is the failure to reflect the concept of rent “top-ups”. These, too, are apparently a common feature of the modern commercial lease, notably for fashion retailers, and provide that the notional rent will be “topped up” with an additional sum determined by the turnover the business does.

Clearly, if these practices are as prevalent as the industry suggests, the register as constructed bears little resemblance to the real rent bill likely to be faced by any tenant.

In terms of providing a timely guide to the market, such weaknesses are compounded by the time it takes to get details of new leases to the public register and by the apparent reluctance of tenants to fill in details accurately, as evidenced by the 8,000 letters now being issued seeking corrected or fuller details just days after the register went public.