Apple has announced a new version of its smartwatch during the "Gather Round" event in Cupertino.

The Apple Watch Series 4 has a new curved display that is 30 per cent larger than the former versions, with 40mm and 44mm models replacing the previous sizes.

In addition, the display now runs to the edges rather than floats in a black bezel, so you get much more screen real estate for your money.

It arrives with a new selection of animated Watch faces and the digital crown has been redesigned. It now comes with haptic feedback.

The speakers have been redesigned too, with greater volume and thump. The microphone has been moved over to the other side to avoid conflicting when speaking to the Watch or taking a phone call.

In terms of build, the rear is now ceramic as standard.

The Apple Watch Series 4 utilises a new S4 chipset to deliver up to two times the performance of the Series 3 device.

Another new feature that has been introduced to Series 4 is the ability to detect a fall. If you or a loved one falls, the Apple Watch can even contact emergency services.

There are new heart rate notifications as well. The Apple Watch can detect if your heart rate is too slow and notify you immediately. The same is true to irregular heart rate rhythms.

A new electrical heart rate sensor also adds ECG features. The electrodes are in the rear of the Watch, built into the back crystal. You can therefore take ECG readings yourself, which are stored in the Health app on your iPhone and could be useful by your doctor if there is anything wrong.

Like the previous Apple Watch, battery life is claimed to be 18 hours, but a charge should last longer for workouts and running than before: 6 hours with GPS.

It will be available in silver, black and gold. Existing Watch bands will still fit even though the new watches are larger.

The Apple Watch Series 4 will be available from 21 September, with orders starting this Friday, 14 September on Apple.com for the UK, or here for the US. Prices start at £399/$399 for the GPS only 40mm version. The cellular model, which will be carried by EE and Vodafone (the latter new for this edition), will start at £499.

The 44mm version with cellular starts at £429.

The existing Apple Watch Series 3 will still be available, starting at £279.