Estimates that time wasted on business travel could lose UK companies over half a billion pounds a year are designed to put the wind up any IT manager considering remote access systems for mobile staff. But it is important to put such figures into perspective and remember that not every employee is either able or willing to spend time working while travelling.

A recent survey, coincidentally compiled by Wi-Fi hotspot provider BT, suggests that staff "waste" up to 689,000 hours a month waiting for flights. Through a series of complex calculations, BT has worked out that the resulting financial loss is £374.85 per employee per month.

Given that, according to somebody's figures (alas, we don't know whose) the total number of business travellers is estimated at 133,192 per month, the total losses equal £49,927,396.05 or £599,128,752.60 per year. This is not quite as random as thinking of any number between one and 100, multiplying it by the sum of the digits that make up today's calendar date, and dividing it by the average number presented by three rolls of a dice. But as spurious generalisations go, these figures have to be almost as spurious and as general as it is possible to get.

The maths in this instance is rendered entirely meaningless by a number of factors, not least being the significant variations between hourly pay rates and the unknowable value of the work that any one employee can usefully do using a notebook PC and a Wi-Fi connection. How many people spend two to three hours reading and replying to business-critical email in any single three-hour period, for instance, and do those working on documents actually need an internet or intranet connection to help them complete their task?

There is also the effect of 24/7 work pressure on the individual to consider. Some workers, myself included, welcome the chance to spend time waiting for the final departure call doing something more productive than counting the number of Da Vinci Code clones in WH Smith. I like writing articles in airport lounges because it gives me more time to sample the pleasures of wherever it is I'm going.

Other people are understandably not so keen to spend every spare minute slaving away with a laptop or smartphone, in many cases because it affords them relatively little advantage to do so, in others because the nature of their profession precludes it. Or just because, like many people in airports, they simply have too many other things to do, like check in and wait in the security queue.

According to our calculations here at IT Week (we can all play the numbers game, thank you) that cost of £374.85 per employee per month, divided by BT's estimated 2.146 flights per person per month, is an order of magnitude too big. We think the real loss is not much more than the average traveller spends on coffee, sandwiches, soft drinks, alcohol or newspapers in the same period of time they could have spent connecting to their company network or the internet. The final point being, which UK businesses does the lack of Wi-Fi connectivity inconvenience? Certainly not WH Smith or Costa Coffee.