Getting lost while driving is a thing of the past thanks to the miracle of satellite navigation. Many cars have built-in sat navs, but millions still don't. These days you can pick up a very basic sat nav for under £100, but with free or cheap smartphone apps to guide you, why bother with a dedicated GPS device? Here we explain which are the best satnavs you can buy in the UK in 2017. See also: How to choose the best satnav

Also see: Best Gadget Deals

We tested out four of the latest satnavs with 5in screens. This is roughly the size of a smartphone screen, but if you don’t fancy carrying a huge phone in your pocket, dedicated units with 6in or 7in screens are available. What’s more, unless you go for one of the few low-cost phablets, large-screen sat navs will almost always be cheaper, especially if you’re mid-contract.

Another advantage of smartphones concerns map data. With a smartphone app, either the maps are stored locally at the expense of a chunk of your phone’s storage, or they’re downloaded on the fly which means using up your monthly data. With a dedicated unit, all your maps are stored locally in memory that you don't need to free up for other purposes. Plus, if you're driving in an area with poor mobile coverage, you might find yourself stranded with no map at all, while a dedicated sat nav always has its map data.

In the case against dedicated in-car units, most have resistive touch screens that are less responsive than the capacitive screen you'll find on every smartphone. However, some of the latest sat navs adopt this technology. Given that you probably spend a lot of your time driving in familiar areas, you won’t always need navigational facilities. Being able to lend out your sat nav is, therefore, another benefit.

A lot of the new dedicated sat navs actually require a smartphone for its data connection. They use this for live traffic data and searching the internet for points of interest. To us, though, this makes no sense: your smartphone already has a GPS receiver so you may as well buy an inexpensive car mount and use that instead.

Of course, dedicated sat navs can have more features than some navigation apps. They include lane assistance which guides you to drive in the correct lane prior to joining or leaving a motorway, and advanced routing features which can, for example, give you the most economical route rather than just the fastest.

Sat nav apps as an alternative

If you're after some good sat nav apps, our colleagues over at Macworld UK have put together a list of the best sat nav apps for iPhone. Many of these apps are also available for Android

Macworld also has a list of the best car mounts for iPhone - a handy gadget if you use your phone as a sat nav.

Now, here are our four favourite dedicated sat nav units currently on sale in the UK.

Garmin nuvi 57LM

Garmin nuvi 57LM
  • RRP: £99.99, US$149.99

This 5in sat nav is one of the best selling on Amazon, and with good reason. For a dedicated device it has every essential function for a budget price.

For the price you get preloaded maps of the UK and Ireland, and Garmin promises free lifetime map updates for the inevitable route and road changes. The nuvi has one of the clearest audio and visual combinations on the market, with features like Lane Assist and Junction View helping to make the sat nav experience as stress-free as possible.

A great addition is the polished Up Ahead feature, which lets you know about places of interest en route to your destination, from restaurants ro cash points and petrol stations. 

TomTom Start 25

TomTom Start 25
  • RRP: £129.99, US$149.90

Much like the Garmin nuvi 57LM, this well-priced 5in sat nav from popular and trusted brand TomTom comes with lifetime map updates. It also ships with Western Europe, not just UK and Ireland.

It has high-end features despite being available for under £100, including speed camera location warnings in real time and parking assist, which can navigate you directly to the best place to park (it won't park for you though, unlucky).

It's easily attached to the dash or windscreen with an integrated mount. The screen cleverly flips to support whichever way round you want to use it. 

TomTom GO 5100

TomTom GO 5100
  • RRP: £259.99

The TomTom GO 5100 is a premium 5in sat nav device. Its high price reflects the fact it has global coverage - you can take it anywhere on the planet and it will give you up to date routes and advice.

It works by shipping with an integrated SIM card with unlimited data - meaning you never have to worry about running out of data, just make sure you can plug it in in the car to keep it charged. 

It has excellent traffic information, and the system smartly reroutes you based on minute by minute traffic changes. It also integrates with the TomTom MyDrive app, allowing you to plan routes in advance on your smartphone or tablet.

Garmin nuvi 2699LMT-D

Garmin nuvi 2699LMT-D
  • RRP: £199.99

This is a good, if pricey, option if you want a larger 6in screen sat nav. It has all the features you'd expect from a modern GPS system, with added clever functions like Bluetooth for hands-free calling integration and the ability to function outside of cellular service.

It also has voice-activated navigation options to minimise the time needed to take your hands off the wheel to use the touchscreen. It also has clever integration with Garmin's Smartphone Link app, allowing you to record detals of your travels such as where you parked, plus send addresses or locations straight from your phone to the sat nav.

It does only come with UK and Ireland maps for the price though, so you'll have to buy other map packs if you want to use it abroad.