The real trouble comes when you stray off route inadvertently and lose your mobile signal - a distinct possibility in the more 'remote' areas of the UK. In these circumstances your handset will simply not be able to direct you until you find yourself back in an area with data reception. I also found that, occasionally, due to the mapping 'corridor' approach, you don't even need to stray that far from your route to venture into a mapping black hole. On one occasion it took nearly a minute to realise I was driving on a road parallel to the one I was supposed to be on - just a couple of hundred metres off-route - before it obliged and recalculated my route.
The system is pretty much useless abroad too, but this isn't entirely Telmap's fault. While Ofcom persists in fannying about, allowing the UK mobile networks to get away with murder, and international data roaming remains at rip-off prices, even the small chunks of data transferred in a Telmap session will start to cost you a fortune as soon as you cross the channel.
Everything else, it seems, is as before. And, unfortunately for Telmap that's a bad thing, because other than for simple route-finding and driving instructions there's not much to it. You cannot, for instance, plan multi-stop routes. Navigating to points on the map rather than by address is slow and unresponsive due to the fact that the map needs to reload every time you pan and zoom. Route optimisations are minimal - only drive and walk (no bicycle or lorry), shortest and fastest options are available, and you can't force the system to route you around a blockage as you can with, for example, a TomTom or with CoPilot.
If you're after a cheap and cheerful sat-nav system and you happen to own a Blackberry with GPS on-board, Telmap navigator will fit the bill nicely. It's easy to use, it'll get you where you want to go without fuss and its pricing structure keeps costs reasonably competitive.
For use abroad or frequent use in the UK, however, it's clear that Telmap Navigator can't compete with software that stores maps locally, or dedicated devices for performance. Its download approach precludes 100 per cent reliability, and the delivery of navigation instructions isn't as polished as they are on the dedicated systems or the best phone sat-nav software.