The highly-anticipated One M9 was announced at Mobile World Congress, in Barcelona earlier this month. 

Boasting a 5inch HD screen, a lightening-fast Qualcomm Snapdragon 810 processor and a 20-megapixel 4K quality rear shooter – on paper, the One M9 is a shoe-in as one of the best phones of 2015.

UK phone carriers have already started taking pre-orders for the polished aluminium smartphone, which will be released on March 31.

Express.co.uk have rounded up some of the best deals available –

Three

The cheapest plan for the upcoming HTC One M9 starts at £39per month.

Three only offers a choice between the Gold on Silver and Grey versions of the 32GB One M9. 

Its 24month plan comes with a reasonable £19 upfront cost and offers unlimited minutes (including free calls to 0800/0808/0500 numbers) and unlimited texts.

Unfortunately, the plan only comes with 1GB of 4G mobile data – which is a little lacklustre for serial mobile surfers 

EE

HTC's latest starts from £31.99per month on EE.

This includes 500MB of mobile 4G data as well as 500minutes and unlimited text messages.

EE's cheapest plan also includes a hefty £199.99 upfront cost for the handset – although it does offer the 32GB model in Grey, Gold and Gold on Silver.

To match Three's 1GB of mobile data, EE customers will need to cough-up £33.49per month which still only includes 500minutes and the same £199.99 upfront cost.

O2

Plans on O2 start from a mere £13.50per month for a 24month contract.

Like EE, this only includes 500MB of mobile 4G data, 500minutes of call time and unlimited text messages.

O2 are asking for a £609.99 upfront cost for either the Gold on Silver or Grey handsets – which is £30 MORE than HTC sells the One M9 SIM-free on Amazon.

To get your hands on the HTC One M9 without an upfront charge costs £42.50per month and comes with 1GB of mobile data, unlimited call times and unlimited texts.

Tesco Mobile

Tesco plans start from £36 and include 1,000 minutes and 5,000 texts. As part of an introductory offer, Tesco Mobile is offering 2GB of 4G mobile data on its cheapest plan.

The supermarket giant claims the deal is for a "limited time only" but has yet to announce when the double data discount will be cut from the price plan.

All of Tesco Mobile's contracts are 24months in length – but none require an upfront cost.

Vodafone

The cheapest Vodafone plan starts at £26.50 per month and includes 100 minutes, unlimited texts and a £169 upfront charge for the smartphone.

However, the plan also comes with a dismal 100MB of 3G mobile data.

Plans which include a 4G connection with Vodafone begin at £38.50per month and include 1GB of mobile data, 600minutes, unlimited texts and a £19 charge for the handset.

Vodafone is one of the few carriers to offer a 12month contract – this starts at £48.50per month and includes 600minutes, unlimited texts, a £249 upfront cost and 1GB of 4G mobile data.

The One M9 is only available in Gold on Silver and Grey on Vodafone.

Giff Gaff

The 'contract-free' mobile network is now selling a SIM-free HTC One M9 for £569 – £10 less expensive than through the manufacturer's own website. 

Giff Gaff say they will dispatch the flagship handset on 31st March 2015 – the phone's official launch date.

The carrier's cheapest plans start from £5per month and include 60 UK minutes, 300 UK texts and just 20MB of 3G internet.

4G plans start at £12per month and offer 500 minutes, unlimited texts and 1 GB of mobile internet data.

Carphone Warehouse 

The HTC One M9 starts £37.50 a month at the Carphone Warehouse with no upfront cost.

The 24month contract is on the O2 network and includes the network's 'Priority Sports' and 'O2 tracks' extras.

Unlimited minutes to any network and unlimited texts are also included in the plan. 

Unfortunately, the contract only comes with 1GB of mobile data – although it is 4G.

And the winner is –

If you can stomach its 1,000 included call-time, Tesco Mobile's lowest cost plan is the most competitive compromise of any UK carrier.