Ofcom Set to Auction Upper 1.4GHz Band for UK 4G and 5G Mobile in 2027

The UK telecoms regulator has today set out their plan to auction off a 25MHz (frequency) slice of the 1.4GHz radio spectrum band (i.e. the “Upper Block” of 1492 to 1517MHz) to mobile operators (EE, O2, Vodafone / Three UK) for use in their 4G and 5G based mobile broadband services, which will take place during the first half of 2027.

Just for some context. The lower part (40MHz) of the L-Band spectrum (i.e 1452 to 1492MHz) is already being used by VodafoneThree to boost their mobile data connectivity (example), albeit mostly as a Supplemental Downlink (SDL) solution. But Ofcom has long been working to clear and re-purpose the additional frequency between 1492 to 1517MHz (here) for use by mobile operators too.

The advantage of 1.4GHz is in the fact that it’s a nicely balanced band that can deliver both a fairly strong level of coverage and fast data speeds, albeit naturally only if the device being used is actually able to harness that extended frequency. Suffice to say that this could make it useful for boosting coverage both indoors and across rural areas (lower frequency signals travel further than higher frequency ones).

However, Ofcom’s plan to auction the upper block of 1.4GHz to mobile operators does note that it sits just below part of the 1.5GHz band, which is being used by Inmarsat‘s emergency communication satellite terminals (i.e. on ships at and near ports, and on aircraft around airports). As such Ofcom’s plan will introduce some temporary limitations on how and where the band can be harnessed.

Ofcom Statement

We will auction 1492-1517 MHz for mobile use. We will award this spectrum in a single round, sealed bid auction, and we will not impose any competition measures in the auction.

There is a risk that use of 1492-1517 MHz for mobile services could cause blocking1 to Inmarsat satellite receivers on ships and aircraft in the 1518-1559 MHz band. This could give rise to risks to safety of life at sea around the coast, and to potential disruption of operations at ports and international airports.

To mitigate these risks, use of this spectrum will be subject to limits on mobile transmissions around the coastline and at certain international airports. We will relax these limits around the coastline on 1 January 2043, and around airports on 1 January 2034. In setting these timeframes we have taken into account significant concerns raised in response to our consultation by the maritime and aviation industries and extensive engagement with the Maritime and Coastguard Agency and the Civil Aviation Authority.

We will not protect either current or future land-based Inmarsat receivers in the 1518-1559 MHz band from potential blocking by mobile services in the 1492-1517 MHz range. We will also not protect programme-making audio links from interference by those mobile services. However, the award winner will not be authorised to begin using 1492-1517 MHz for mobile services before 11 June 2027, at least one year from the date of this statement, to give these users time to implement mitigation measures before the risk of blocking arises.

The overview section in this document is a simplified high-level summary only. The decisions we have taken and our reasoning are set out in the full document.

The compromise allows existing users, those likely to be most impacted by the auction (particularly in the maritime and aviation sectors where safety is paramount), time to adapt their systems to cope with the change.

Ofcom expects to publish their draft Auction Regulations consultation later this summer 2026, before then conducting the auction itself sometime in the first half of 2027. We suspect VodafoneThree will strongly desire to acquire the block nearest to their existing spectrum holding.